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Автор: Grafiati
Опубліковано: 7 липня 2024
Оновлено: 7 липня 2024

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Статті в журналах з теми "Phonon energy":

1

Dovlatova, Alla, and Dmitri Yerchuck. "Quantum Field Theory of Dynamics of Spectroscopic Transitions by Strong Dipole-Photon and Dipole-Phonon Coupling." ISRN Optics 2012 (December 12, 2012): 1–10. http://dx.doi.org/10.5402/2012/390749.

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Matrix-operator difference-differential equations for dynamics of spectroscopic transitions in 1D multiqubit exchange-coupled (para)magnetic and optical systems by strong dipole-photon and dipole-phonon coupling are derived within the framework of quantum field theory. It has been established that by strong dipole-photon and dipole-phonon coupling the formation of long-lived coherent system of the resonance phonons takes place, and relaxation processes acquire pure quantum character. It is determined by the appearance of coherent emission process of EM-field energy, for which the resonance phonon system is responsible. Emission process is accompanied by phonon Rabi quantum oscillation, which can be time-shared from photon quantum Rabi oscillations, accompanying coherent absorption process of EM-field energy. For the case of radio spectroscopy, it corresponds to the possibility of the simultaneous observation along with (para)magntic spin resonance, the acoustic spin resonance.
2

Zhao, Feng Qi, and Xiao Mei Dai. "Influence of Pressure on Polaron Energy in a Wurtzite GaN/AlxGa1-xN Quantum Well." Solid State Phenomena 288 (March 2019): 17–26. http://dx.doi.org/10.4028/www.scientific.net/ssp.288.17.

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The influence of hydrostatic pressure on the polaron energy level in wurtzite GaN/AlxGa1-xN quantum well is studied by a Lee-Low-Pines variational method, and the numerical results of the ground state energy, transition energy and contributions of different phonons to polaron energy (polaron effects) are given as functions of pressurepand compositionx. The results show that the ground state energy and transition energy in the wurtzite GaN/AlxGa1-xN quantum well decrease with the increase of the hydrostatic pressurep, and increase with the increase of the compositionx. The contributions of different phonons to polaron energy with pressurepand compositionxare obviously different. With the increase of hydrostatic pressure, the contribution of half-space phonon, confined phonon and the total contribution of phonons of all branches increases obviously, while the contribution of interface phonon slowly increases. During the increase of the composition, the contribution of interface phonon decreases and the contribution of half-space phonon increases slowly, while the contribution of confined phonon and the total contribution of phonons increases significantly. In general, the electron-optical phonon interaction play an important role in electronic states of GaN/AlxGa1-xN quantum wells and can not be neglected.
3

Kang, Nam Lyong, and Sang Don Choi. "Projection-Reduction Approach to Optical Conductivities for an Electron-Phonon System and Their Diagram Representation." ISRN Condensed Matter Physics 2014 (April 7, 2014): 1–23. http://dx.doi.org/10.1155/2014/719120.

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Utilizing state-dependent projection operators and the Kang-Choi reduction identities, we derive the linear, first, and second-order nonlinear optical conductivities for an electron system interacting with phonons. The lineshape functions included in the conductivity tensors satisfy “the population criterion” saying that the Fermi distribution functions for electrons and Planck distribution functions for phonons should be combined in multiplicative forms. The results also contain energy denominator factors enforcing the energy conservation as well as interaction factors describing electron-phonon interaction properly. Therefore, the phonon absorption and emission processes as well as photon absorption and emission processes in all electron transition processes can be presented in an organized manner and the results can be represented in diagrams that can model the quantum dynamics of electrons in a solid.
4

Jin, Jae Sik, and Joon Sik Lee. "Electron–Phonon Interaction Model and Prediction of Thermal Energy Transport in SOI Transistor." Journal of Nanoscience and Nanotechnology 7, no. 11 (November 1, 2007): 4094–100. http://dx.doi.org/10.1166/jnn.2007.010.

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An electron–phonon interaction model is proposed and applied to thermal transport in semiconductors at micro/nanoscales. The high electron energy induced by the electric field in a transistor is transferred to the phonon system through electron–phonon interaction in the high field region of the transistor. Due to this fact, a hot spot occurs, which is much smaller than the phonon mean free path in the Si-layer. The full phonon dispersion model based on the Boltzmann transport equation (BTE) with the relaxation time approximation is applied for the interactions among different phonon branches and different phonon frequencies. The Joule heating by the electron–phonon scattering is modeled through the intervalley and intravalley processes for silicon by introducing average electron energy. The simulation results are compared with those obtained by the full phonon dispersion model which treats the electron–phonon scattering as a volumetric heat source. The comparison shows that the peak temperature in the hot spot region is considerably higher and more localized than the previous results. The thermal characteristics of each phonon mode are useful to explain the above phenomena. The optical mode phonons of negligible group velocity obtain the highest energy density from electrons, and resides in the hot spot region without any contribution to heat transport, which results in a higher temperature in that region. Since the acoustic phonons with low group velocity show the higher energy density after electron–phonon scattering, they induce more localized heating near the hot spot region. The ballistic features are strongly observed when phonon–phonon scattering rates are lower than 4 × 1010 s−1.
5

Jin, Jae Sik, and Joon Sik Lee. "Electron–Phonon Interaction Model and Prediction of Thermal Energy Transport in SOI Transistor." Journal of Nanoscience and Nanotechnology 7, no. 11 (November 1, 2007): 4094–100. http://dx.doi.org/10.1166/jnn.2007.18084.

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An electron–phonon interaction model is proposed and applied to thermal transport in semiconductors at micro/nanoscales. The high electron energy induced by the electric field in a transistor is transferred to the phonon system through electron–phonon interaction in the high field region of the transistor. Due to this fact, a hot spot occurs, which is much smaller than the phonon mean free path in the Si-layer. The full phonon dispersion model based on the Boltzmann transport equation (BTE) with the relaxation time approximation is applied for the interactions among different phonon branches and different phonon frequencies. The Joule heating by the electron–phonon scattering is modeled through the intervalley and intravalley processes for silicon by introducing average electron energy. The simulation results are compared with those obtained by the full phonon dispersion model which treats the electron–phonon scattering as a volumetric heat source. The comparison shows that the peak temperature in the hot spot region is considerably higher and more localized than the previous results. The thermal characteristics of each phonon mode are useful to explain the above phenomena. The optical mode phonons of negligible group velocity obtain the highest energy density from electrons, and resides in the hot spot region without any contribution to heat transport, which results in a higher temperature in that region. Since the acoustic phonons with low group velocity show the higher energy density after electron–phonon scattering, they induce more localized heating near the hot spot region. The ballistic features are strongly observed when phonon–phonon scattering rates are lower than 4 × 1010 s−1.
6

Rodrigues, Ligia M. C. S., and Stenio Wulck. "q-Deformation and Energy Deficit in Liquid Helium Phonon Spectrum." Modern Physics Letters B 11, no. 07 (March 20, 1997): 297–301. http://dx.doi.org/10.1142/s0217984997000372.

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We present an application of an ideal bosonic q-gas in a ν0 inequivalent representation to the phonons in 4 He and discuss the role of q-deformation as a possible mechanism to supply the energy deficit that forbiddens one-phonon decay into two phonons when the constant γ in the phonon anomalous dispersion relation (ωph = c0p(1 - γp2)) is positive.
7

Bin Mansoor, Saad, and Bekir Sami Yilbas. "Nonequilibrium cross-plane energy transport in aluminum–silicon–aluminum wafer." International Journal of Modern Physics B 29, no. 17 (June 23, 2015): 1550112. http://dx.doi.org/10.1142/s021797921550112x.

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Transient phonon transport across cross-planes of aluminum–silicon–aluminum combined films is investigated and the Boltzmann transport equation is incorporated to formulate the energy transport in the combined films. Since electrons and phonons thermally separate in the thin aluminum film during heating, the Boltzmann equation is used separately in the electron and lattice subsystems to account for the energy transport in the aluminum film. Electron–phonon coupling is incorporated for the energy exchange between electron and lattice subsystems in the film. Thermal boundary resistance (TBR) is introduced at the interfaces of the silicon–aluminum films. In order to examine the ballistic contribution of phonons on the phonon intensity distribution in the silicon film, frequency-dependent solution of the Boltzmann equation is used in the silicon film and the film thickness is varied to investigate the size effect on the thermal conductivity in the film. It is found that equivalent equilibrium temperature of phonons remains high at silicon–aluminum interface because of the ballistic contribution of the phonons. Equivalent equilibrium temperature for the electron subsystem becomes higher than that corresponding to phonon temperature at the aluminum–silicon interface.
8

MATULIONIS, A., J. LIBERIS, L. ARDARAVIČIUS, J. SMART, D. PAVLIDIS, S. HUBBARD, and L. F. EASTMAN. "HOT-PHONON LIMITED ELECTRON ENERGY RELAXATION IN AlN/GaN." International Journal of High Speed Electronics and Systems 12, no. 02 (June 2002): 459–68. http://dx.doi.org/10.1142/s0129156402001381.

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Microwave noise technique is applied to study energy dissipation in an AlN/GaN heterostructure containing a two-dimensional electron gas channel. Measurements of the dissipated power and the noise temperature are performed at 80 K lattice temperature in the electric field range up to 40 kV/cm. The energy relaxation time is found to decrease from 40 ps to 0.55 ps when the bias is increased. The experimental data are discussed in the electron temperature approximation assuming electron energy dissipation on optical phonons and hot-phonon effects. Dependencies of the hot-phonon number and the hot-phonon temperature on the hot-electron temperature are deduced. The frequency cutoff imposed by the limited energy dissipation through optical phonons is estimated.
9

Zhou, Jiawei, Bolin Liao, Bo Qiu, Samuel Huberman, Keivan Esfarjani, Mildred S. Dresselhaus, and Gang Chen. "Ab initio optimization of phonon drag effect for lower-temperature thermoelectric energy conversion." Proceedings of the National Academy of Sciences 112, no. 48 (November 16, 2015): 14777–82. http://dx.doi.org/10.1073/pnas.1512328112.

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Although the thermoelectric figure of merit zT above 300 K has seen significant improvement recently, the progress at lower temperatures has been slow, mainly limited by the relatively low Seebeck coefficient and high thermal conductivity. Here we report, for the first time to our knowledge, success in first-principles computation of the phonon drag effect—a coupling phenomenon between electrons and nonequilibrium phonons—in heavily doped region and its optimization to enhance the Seebeck coefficient while reducing the phonon thermal conductivity by nanostructuring. Our simulation quantitatively identifies the major phonons contributing to the phonon drag, which are spectrally distinct from those carrying heat, and further reveals that although the phonon drag is reduced in heavily doped samples, a significant contribution to Seebeck coefficient still exists. An ideal phonon filter is proposed to enhance zT of silicon at room temperature by a factor of 20 to ∼0.25, and the enhancement can reach 70 times at 100 K. This work opens up a new venue toward better thermoelectrics by harnessing nonequilibrium phonons.
10

Sen, R., N. Vast, and J. Sjakste. "Hot electron relaxation and energy loss rate in silicon: Temperature dependence and main scattering channels." Applied Physics Letters 120, no. 8 (February 21, 2022): 082101. http://dx.doi.org/10.1063/5.0082727.

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In this work, we revisit the density functional theory (DFT)-based results for electron–phonon scattering in highly excited silicon. Using the state-of-the-art ab initio methods, we examine the main scattering channels, which contribute to the total electron–phonon scattering rate and the energy loss rate of photoexcited electrons in silicon as well as their temperature dependence. Both temperature dependence and the main scattering channels are shown to strongly differ for the total electron–phonon scattering rate and the energy loss rate of photoexcited electrons. While the total electron–phonon scattering rate increases strongly with temperature, the temperature dependence of the energy loss rate is negligible. Also, while acoustic phonons dominate the total electron–phonon scattering rate at 300 K, the main contribution to the energy loss rate comes from optical modes. In this respect, DFT-based results are found to disagree with conclusions of Fischetti et al. [Appl. Phys. Lett. 114, 222104 (2019)]. We explain the origin of this discrepancy, which is mainly due to differences in the description of the electron–phonon scattering channels associated with transverse phonons.
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Статті в журналах Дисертації Книги

Дисертації з теми "Phonon energy":

1

Hanna, Ann Catrina. "Energy resolved phonon scattering in glasses." Thesis, University of Glasgow, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280020.

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2

Ong, Pang-Leen. "PHONON-ENERGY-COUPLING-ENHANCEMENT EFFECT AND ITS APPLICATIONS." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/652.

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Silicon Oxide/Oxynitride (SiO2/SiON) has been the mainstream material used for gate dielectric for MOS transistors for the past 30 years. The aggressive scaling of the feature size of MOS transistor has limited the ability of SiO2/SiON to work effectively as the gate dielectric to modulate the conduction of current of MOS transistors due to excess leakage current dominated by direct quantum tunneling. Due to this constraint, alternative gate dielectric/high-k is being employed to reduce the leakage current in order to maintain the rate of scaling of MOS transistors. However, the cost involved in the implementation of these new gate dielectric materials are high due to the requirements of a change in the process flow for device fabrication. This work presents the results of a novel processing method implementing the use of rapid thermal processing (RTP) on conventional SiO2/SiON gate dielectric to reduce the gate leakage current by three to five orders of magnitude. Electrical properties of the effect were characterized on fabricated MOS capacitors using semiconductor parameter analyzer and LCR meter. Material characterization was performed using FT-IR to understand the mechanism involved in this novel processing method, named PECE (Phonon-Energy-Coupling-Enhancement). By implementing this novel process, the use of SiO2/SiON as gate dielectric can be scaled further in conventional process flow of device fabrication.
3

Damart, Tanguy. "Energy dissipation in oxide glasses." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1189/document.

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L'atténuation d'ondes à basse et haute fréquences dans les verres n'est pas encore bien comprise en grande partie car les phénomènes à l'origine de cette dissipation varient grandement en fonction de la fréquence. L’existence de structures complexes et organisation multi échelle dans les verres favorise l'apparition de temps de relaxation allant de la seconde à la femtoseconde et de corrélation prenant place de l’Angström à la centaine de nanomètre. A basse fréquence, une meilleur compréhension de ces phénomènes de dissipation serait bénéfique à de nombreux domaines. Par exemple, les multi-couches recouvrants les miroirs des interféromètres servant à détecter les ondes gravitationnelles sont réalisées à partir de verres d'oxyde (SiO2 et Ta2O5) qui sont une source majeur de dissipation. A haute fréquence, l'étude de la dissipation pose des questions théoriques sur le lien entre asymétrie locale et atténuation acoustique.Durant cette étude, nous avons réalisé une analyse approfondie de l'interaction entre ondes mécaniques et structure des verres en utilisant des techniques de simulations telle que la dynamique moléculaire. En partant de la synthèse de verres de SiO2 et Ta2O5, nous nous sommes appliqués à trouver l'origine structurelle de la dissipation aux différentes échelles de fréquence. A basse fréquence nous avons été capable de catégoriser les déplacements atomiques à l'origine de la dissipation en utilisant la théorie des états à deux niveaux. A haute fréquence, nous avons utilisé une technique de spectroscopie mécanique appuyé par un développement analytique pour montrer l'importance du désordre local dans l’existence de dissipation
The origin of sound attenuation at low and high frequency in glasses stays elusive mainly because of the complex temperature and frequency dependence of the phenomena at its root. Indeed, the presence of complex structures and multi-scale organizations in glasses induce the existence of relaxation time ranging from the second to the femto-second and of spatial correlation ranging from the Angström to a hundred nanometers. At low-frequency, a better understanding of the phenomena at the origin of dissipation would be beneficial to several applications. For example, the multi-layers coating the mirrors of gravitational waves detectors consists of a superposition of two oxide glasses: silicate (SiO2) and tantalum pentoxide (Ta2O5), are an important source of dissipation. At high frequency, the study of dissipation raises theoretical questions about the link between attenuation and dissipation as well as between loclt asymmetry and dissipation. In the present study, we conducted an analysis of the interaction between mechanical waves and the structure of two oxide glasses using simulation techniques such as non-equilibrium molecular dynamics. At high-frequencies, we implemented and used mechanical spectroscopy to measure dissipation numerically and performed in parallel an analytical development based on the projection of the atomic motion on the vibrational eigenmodes. At low-frequencies, we used molecular dynamics to gather sets of thermally activated events that we classed in three categories based on topologically distinct atomic motions and from which we predicted dissipation numerically using a refreshed TLS model
4

Kulikowski, Anoushka. "Phonon studies of energy loss in vertical tunnelling structures." Thesis, Lancaster University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286990.

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5

Giltrow, M. "Phonon study of vertical resonant structures." Thesis, Lancaster University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337346.

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6

Sklan, Sophia Robin. "Dynamical tuning of phonon transport for information and energy control." Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/103231.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 145-164).
Controlled transport of energy and information is of paramount importance. It remains challenging, however, partially from the difficulty in controlling their physical carriers. Steering electrons and photons is now routine, yet atomic vibrations (quantized as phonons) are hard to control. This is partly due to the centrality of phonons in the disordered transport of energy as heat, but even in ordered sound waves problems persist. Phonons can readily couple to each other or to other degrees of freedom, degrading their energy or information content. Reversing these couplings, thereby regulating atomic motion, only recently became plausible. This increased control would reduce parasitic losses and turn phonons into information carriers. Dynamical effects are a crucial and under-examined aspect of this control as static devices are insufficient for changing external conditions. Dynamical control adds flexibility and versatility to phononic systems. Essentially, dynamical control requires tunable materials, materials whose physical properties depend on an external signal. Dynamical tuning is sensitive to the relative frequencies of the tuning signal and the controlled phonons. We develop an intuitive framework of the temporal modulation regimes. In low frequency tuning, phonons can adapt adiabatically to the material's changes. A variety of signals can be temporally and spatially modulated to tune phonon transport in this regime. We apply this adiabatic perspective to analyze dynamical effects in thermal cloaks. Tuning signals near the frequency of some phonon mode can produce resonant couplings. This hybridization can produce large changes in phonon properties. We apply this hybridization to develop a rigorously nonreciprocal phononic computer using magneto-acoustic materials that can outperform conventional computers in some tasks. At high frequencies, phonons can only respond perturbatively to the tuning signal's changes. This regime is generally limited to optical control but it opens up new avenues for control. Employing an alternative approach to optical coupling, we develop a model of inverse acousto-optics (tuning the speed of sound with optical intensity) and dynamical phonon localization.
by Sophia Robin Sklan.
Ph. D.
7

Chen, Dye-Zone A. (Dye-Zone Abraham) 1973. "Energy transmission through and along thin films mediated by surface phonon-polaritons." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42067.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 131-138).
Surface phonon-polaritons are hybrid electromagnetic modes that are the result of photons coupling to transverse optical phonons. Recently, these surface modes have received much renewed interest primarily due to the fact that micro-fabrication techniques can now routinely create structures at the length scales of interest (nanometers to microns). This thesis investigates the transmission of energy mediated by surface phonon-polaritons. First, the heat flux transported along the in-plane direction of a thin film is explored. A kinetic theory-based calculation is performed using a diffusion approximation. These results are further confirmed by simulations using fluctuational electrodynamics. It was found that for amorphous silicon dioxide films tens of nanometers thick, the in-plane heat flux carried by surface phonon-polaritons can exceed the heat flux carried by phonons in the film. The results also show that the effective thermal conductivity due to surface polaritons increases with decreasing film thickness, offering a method to potentially offset the reduction in thermal conductivity due to increased interface scattering of phonons in crystalline thin films. Both calculations point to the propagation length of the surface phonon-polariton as the source for the large heat flux. An experimental measurement of the surface phononpolariton propagation length on amorphous silicon dioxide is performed using attenuated total reflection and is found to agree well with the calculated value. The last part of this thesis examines the energy transmission in the direction normal to the plane of the film. Specifically, the transmission of light through an amorphous silicon dioxide film perforated by sub-wavelength holes is experimentally measured. A five-fold increase through the perforated film versus through a solid film is observed in discrete frequency ranges, which strongly suggests the involvement of surface phonon-polaritons.
by Dye-Zone A. Chen.
Ph.D.
8

Minnich, Austin Jerome. "Exploring electron and phonon transport at the nanoscale for thermoelectric energy conversion." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67593.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.
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Includes bibliographical references (p. 147-155).
Thermoelectric materials are capable of solid-state direct heat to electricity energy conversion and are ideal for waste heat recovery applications due to their simplicity, reliability, and lack of environmentally harmful working fluids. Recently, nanostructured thermoelectrics have demonstrated remarkably enhanced energy conversion efficiencies, primarily due to a reduction in lattice thermal conductivity. Despite these advances, much remains unknown about heat transport in these materials, and further efficiency improvements will require a detailed understanding of how the heat carriers, electrons and phonons, are affected by nanostructures. To elucidate these processes, in this thesis we investigate nanoscale transport using both modeling and experiment. The first portion of the thesis studies how electrons and phonons are affected by grain boundaries in nanocomposite thermoelectric materials, where the grain sizes are smaller than mean free paths (MFPs). We use the Boltzmann transport equation (BTE) and a new grain boundary scattering model to understand how thermoelectric properties are affected in nanocomposites, as well as to identify strategies which could lead to more efficient materials. The second portion of the thesis focuses on determining how to more directly measure heat carrier properties like frequency-dependent MFPs. Knowledge of phonon MFPs is crucial to understanding and engineering nanoscale transport, yet MFPs are largely unknown even for bulk materials and few experimental techniques exist to measure them. We show that performing macroscopic measurements cannot reveal the MFPs; instead, we must study transport at the scales of the MFPs, in the quasi- ballistic transport regime. To investigate transport at these small length scales, we first numerically solve the frequency-dependent phonon BTE, which is valid even in the absence of local thermal equilibrium, unlike heat diffusion theory. Next, we introduce a novel thermal conductivity spectroscopy technique which can measure MFP distributions over a wide range of length scales and materials using observations of quasi-ballistic heat transfer in a pump-probe experiment. By observing the changes in thermal resistance as a heated area size is systematically varied, the thermal conductivity contributions from different MFP phonons can be determined. We present the first experimental measurements of the MFP distribution in silicon at cryogenic temperatures. Finally, we develop a modification of this technique which permits us to study transport at scales much smaller than the diffraction limit of approximately one micron. It is important to access these length scales as many technologically relevant materials like thermoelectrics have MFPs in the deep submicron regime. To beat the diffraction limit, we use electron-beam lithography to pattern metallic nano dot arrays with diameters in the hundreds of nanometers range. Because the effective length scale for heat transfer is the dot diameter rather than the optical beam diameter, we are able to study nanoscale heat transfer while still achieving ultrafast time resolution. We demonstrate the modified technique by measuring the MFP distribution in sapphire. Considering the crucial importance of the knowledge of MFPs to understanding and engineering nanoscale transport, we expect these newly developed techniques to be useful for a variety of energy applications, particularly for thermoelectrics, as well as for gaining a fundamental understanding of nanoscale heat transport.
by Austin Jerome Minnich.
Ph.D.
9

Mafra, Daniela Lopes. "Using inelastic scattering of light to understand the nature of electron-phonon interactions and phonon self-energy renormalizations in graphene materials." Universidade Federal de Minas Gerais, 2012. http://hdl.handle.net/1843/MPDZ-8Y4GEG.

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In the last decade, many theoretical and experimental achievements have been made in the physics of graphene. In particular, Raman spectroscopy has been playing an important role in unraveling the properties of graphene systems. In this thesis we use the Raman spectroscopy to study some effects of the electron-phonon coupling in monolayer and bilayer graphene and to probe the electronic and vibrational structure of bilayer graphene. Phonon self-energy corrections have mostly been studied theoretically and experimentally for phonon modes with zone-center (q = 0) wavevectors. Here, we combine Raman spectroscopy and gate voltage to study phonons of monolayer graphene for the features originated from a double-resonant Raman (DRR) process with q .= 0 wavevectors. We observe phonon renormalization effects in which there is a softening of the frequency and a broadening of the decay width with increasing the gate voltage, that is opposite from what is observed for the zone-center q = 0 case. We show that this renormalization is a signature for the phonons with q . 2k wavevector that come from both intravalley and intervalley DRR processes. Within this framework, we resolve the identification of the phonon modes contributing to the G. Raman feature, at ¡­ 2450 cm.1, and also for five second order Raman combination modes in the frequency range of 1700 . 2300 cm.1 of monolayer graphene. By combining the DRR theory with the anomalous phonon renormalization effect, we show a new technique for using Raman spectroscopy to identify the proper phonon mode assignment for each combination mode. We also study the behavior of the optical phonon modes in bilayer graphene devices by applying top gate voltage, using Raman scattering. We observe the splitting of the Raman G band as we tune the Fermi level of the sample, which is explained in terms of mixing of the Raman (Eg) and infrared (Eu) phonon modes, due to different doping in the two layers. We show that the comparison between the experiment and theoretical model not only gives information about the total charge concentration in the bilayer graphene device, but also allows to separately quantify the amount of unintentional charge coming from the top and the bottom of the system, and therefore to characterize the intrinsic charges of bilayer graphene with its surrounding environment. In the second part of this thesis, the dispersion of electrons and phonons near the K point of bilayer graphene was investigated in a resonant Raman study of the G¡Ç band using different laser excitation energies in the near-infrared and visible range. The electronic structure was analyzed within the tight-binding approximation, and the Slonczewski-Weiss-McClure (SWM) parameters were obtained from the analysis of the dispersive behavior of the G¡Ç band considering both the inner and the outer DRR processes. We show that the SWM parameters obtained considering the inner process are in better agreement with those obtained from other experimental techniques, strongly suggesting that the inner process is the main responsible for the G¡Ç feature in graphene. Additionally, the dependence of the intensity of the four peaks that compose the G¡Ç band of bilayer graphene with laser excitation energy and laser power is explored and explained in terms of the electron-phonon coupling and the relaxation of the photon-excited electron. We show that the carrier relaxation occurs predominantly by emitting a lowenergy acoustic phonon and the different combinations of relaxation processes determine the relative intensities of the four peaks that give rise to the G¡Ç band. Some peaks show an increase of their intensity at the expense of others, thereby making the intensity of the peaks both different from each other and dependent on laser excitation energy and on power level. This effect gives important information about the electron and phonon dynamics and needs to be taken into account for certain applications of bilayer graphene in the field of nanotechnology.
Na última década, muitos avanços teóricos e experimentais foram alcançados na física do grafeno. Em particular, a Espectroscopia Raman tem sido muito importante para elucidar propriedades físicas e químicas em sistemas de grafeno. Nessa tese nós usamos a Espectroscopia Raman para estudar alguns dos efeitos do acoplamento elétron-fônon no grafeno de camada única e de dupla camada e para obter informações sobre a estrutura eletrônica e vibracional do grafeno de camada dupla. As renormalizações das energias dos fônons tem sido estudadas basicamente para fônons com vetor de onda nulo (q=0). Aqui, nós combinamos a Espectroscopia Raman com aplicação de tensão de porta, para estudar, em grafeno de camada única, as bandas originadas do processo Raman com dupla ressonância (DDR) com etores de onda q0. Nós observamos os efeitos de decaimento dos fônons com o aumento da tensão de porta e esse efeito é o oposto do que é observado para os fônons com q=0. Nós mostramos que esse tipo de renormalização é uma assinatura dos fônons com vetor de onda q2K que vem de um processo de camada única, os modos de fônons que contribuem para a banda Raman G*, em ~2450cm-1 e para outros cinco picos provenientes de combinação de modos na região de frequência 1700-2300cm-1. Combinando a teoria do processo DRR com o efeito de renormalização de fônons, nós mostramos uma nova técnica para usar a Espectroscopia Raman para identificar cada modo Raman apropriadamente. Nó também estudamos o comportamento dos modos ópticos do grafeno de camada dupla combinando o espalhamento Raman e a aplicação de tensão de porta em dispositivos desse material. Nós observamos que a banda G se divide em duas quando o nível de Fermi da amostra é mudado e isso é explicado em termos da mistura dos modos de fônon Raman (Eg) e infravermelho (Eu) devido a diferença de concentração de carga nas duas camadas. Nós mostramos que a comparação entre os dados experimentais e o modelo teórico não dá apenas informação sobre a concentração de carga total no dispositivo de grafeno de camada dupla, mas também nos permite quantificar separadamente a quantidade de cargas não intencionais provenientes da camada de cima e de baixo do sistema e, portanto caracterizar a interação do grafeno de camada dupla com o ambiente a sua volta. Na segunda parte dessa tese, a dispersão de elétrons e fônons perto do ponto K do grafeno de camada dupla é investigada atravé do estudo da banda G' usando várias energias de excitação de laser na região do infravermelho e do visível. A estrutura eletrônica foi analisada dentro da aproximação de ligações-forte e os parâmetros Slonczewski-Weiss-McClure (SWM) foram obtidos através do comportamento dispersivo da banda G' considerando-se tanto o processo DRR interno, quanto o externo. Nós mostramos que os parâmetros SWM obtidos considerando-se que o processo DRR interno está em melhor acordo com os valores obtidos por outras técnicas experimentais, sugerindo fortemente que o processo interno é o principal responsável pela banda G' no grafeno. Além disso, a dependência da intensidade dos quatro picos que compõe a banda G' do grafeno de camada dupla com a energia de excitação de laser e com a potência do laser é explorada e explicada em termos do acoplamento elétron-fônon e do relaxamento dos elétrons foto-excitados. Nós mostramos que o relaxamento dos elétrons ocorre predominantemente pela emissão de fônons acústicos de baixa energia e as diferentes combinações dos processos de relaxamento determinam as intensidades relativas dos quatro picos que dão origem à banda G'. Esse efeito nos fornece informações importantes sobre a dinâmica dos elétrons e fônons e precisa ser levado em conta para aplicações do grafeno de camada dupla do campo nanotecnológico.
10

Sidorova, Mariia. "Timing Jitter and Electron-Phonon Interaction in Superconducting Nanowire Single-Photon Detectors (SNSPDs)." Doctoral thesis, Humboldt-Universität zu Berlin, 2021. http://dx.doi.org/10.18452/22296.

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Die vorliegende Doktorarbeit beschäftigt sich mit der experimentellen Studie zweier miteinander verbundener Phänomene: Dem intrinsischen Timing-Jitter in einem supraleitendenden Nanodraht-Einzelphotonen-Detektor (SNSPD) und der Relaxation der Elektronenenergie in supraleitenden Filmen. Supraleitende Nanodrähte auf einem dielektrischen Substrat als mikroskopische Grundbausteine jeglicher SNSPDs stellen sowohl für theoretische als auch für experimentelle Studien komplexe Objekte dar. Die Komplexität ergibt sich aus der Tatsache, dass SNSPDs in der Praxis stark ungeordnete und ultradünne supraleitende Filme verwenden, die eine akustische Fehlanpassung zu dem zugrundeliegenden Substrat aufweisen und einen Nichtgleichgewichts-Zustand implizieren. Die Arbeit untersucht die Komplexität des am weitesten in der SNSPD Technologie verbreiteten Materials, Niobnitrid (NbN), indem verschiedene experimentelle Methoden angewandt werden. Als eine mögliche Anwendung der SNSPD-Technologie wird ein Prototyp eines dispersiven Raman-Spektrometers mit Einzelphotonen-Sensitivität demonstriert.
This Ph.D. thesis is based on the experimental study of two mutually interconnected phenomena: intrinsic timing jitter in superconducting nanowire single-photon detectors (SNSPDs) and relaxation of the electron energy in superconducting films. Microscopically, a building element of any SNSPD device, a superconducting nanowire on top of a dielectric substrate, represents a complex object for both experimental and theoretical studies. The complexity arises because, in practice, the SNSPD utilizes strongly disordered and ultrathin superconducting films, which acoustically mismatch with the underlying substrate, and implies a non-equilibrium state. This thesis addresses the complexity of the most conventional superconducting material used in SNSPD technology, niobium nitride (NbN), by applying several distinct experimental techniques. As an emerging application of the SNSPD technology, we demonstrate a prototype of the dispersive Raman spectrometer with single-photon sensitivity.
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Книги з теми "Phonon energy":

1

1905-, Fröhlich H., Barrett T. W. 1939-, and Pohl Herbert A. 1916-, eds. Energy transfer dynamics: Studies and essays in honor of Herbert Fröhlich on his eightieth birthday. Berlin: Springer-Verlag, 1987.

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2

National Research Council (U.S.). Committee on Potential Applications of Concentrated Solar Photons. Potential applications of concentrated solar photons: A report prepared by the Committee on Potential Applications of Concentrated Solar Photons, Energy Engineering Board, Commission on Engineering and Technical Systems, National Research Council. Washington, D.C: National Academy Press, 1991.

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3

International Symposium on Quasiparticle and Phonon Excitations in Nuclei (1999 RIKEN, Japan). International Symposium on Quasiparticle and Phonon Excitations in Nuclei (Soloviev 99): In memory of Professor Vadim Soloviev (1925-1998), RIKEN, Wako, Saitama, Japan, 4-7 December 1999. Edited by Arima Akito 1930-, Dang Nguyen Dinh, Solovʹev V. G, and Rikagaku Kenkyūjo (Japan). Singapore: World Scientific, 2000.

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4

Andrée, Dutreix, and European Society for Therapeutic Radiology and Oncology, eds. Monitor unit calculation for high energy photon beams. Leuven: Garant Publishers, 1997.

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5

Evans, Myron W. The enigmatic photon. Dordrecht: Kluwer Academic Publishers, 1994.

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6

NATO Advanced Study Institute on the Physics of the Two-Dimensional Electron Gas (1986 Oostduinkerke, Belgium). The physics of the two-dimensional electron gas. New York: Plenum Press, 1987.

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7

Radwan, Ayman, and Jonathan Rodriguez, eds. Energy Efficient Smart Phones for 5G Networks. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-10314-3.

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8

Ben, Mijnheer, ed. Monitor unit calculation for high energy photon beams: Practical examples. Brussels: Estro, 2001.

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9

Taniguchi, Norio. Energy-beam processing of materials: Advanced manufacturing using various energy sources. Oxford: Clarendon Press, 1989.

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10

International Symposium on Lepton and Photon Interactions at High Energies (20th 2001 Rome, Italy). XX International Symposium on Lepton and Photon Interactions at High Energies: Lepton-Photon 01. Edited by Lee-Franzini Juliet, Franzini Paolo, Bossi Fabio, and World Scientific (Firm). New Jersey: World Scientific, 2002.

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Частини книг з теми "Phonon energy":

1

Benedek, Giorgio. "Vibrational Energy Exchange Between Gases and Solids." In Nonequilibrium Phonon Dynamics, 601–21. Boston, MA: Springer US, 1985. http://dx.doi.org/10.1007/978-1-4613-2501-7_11.

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2

Sun, Chang Q. "Theory: Bond-Electron-Energy Correlation." In Electron and Phonon Spectrometrics, 25–44. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-3176-7_2.

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3

Singh, Jai. "Exciton-Phonon Interactions." In Excitation Energy Transfer Processes in Condensed Matter, 47–67. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4899-0996-1_2.

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4

Gronert, H. W., D. M. Herlach, and G. V. Lecomte. "Phonon Scattering by Low-Energy Excitations and Free Volume in Amorphous PdCuSi." In Phonon Scattering in Condensed Matter V, 46–48. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-82912-3_13.

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5

Vickers, A. J., N. Balkan, M. Cankurtaran, and H. Çelik. "Acoustic Phonon Assisted Energy Relaxation of 2D Electron Gases." In Hot Carriers in Semiconductors, 437–39. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4613-0401-2_100.

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6

Maschhoff, K. R., E. Drescher-Krasicka, and A. V. Granato. "Ultrasonic Detection of an Energy Gap Change in the N/S Transition for Trapped H in Nb." In Phonon Scattering in Condensed Matter V, 64–66. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-82912-3_19.

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7

Eyles, R. H., C. J. Mellor, A. J. Kent, L. J. Challis, S. Kravchenko, N. Zinov’ev, and M. Henini. "Phonon Measurements of the Energy Gap in the Fractional Quantum Hall State." In Die Kunst of Phonons, 201–3. Boston, MA: Springer US, 1994. http://dx.doi.org/10.1007/978-1-4615-2455-7_19.

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8

Isaenko, Ludmila, Alexander Yelisseyev, Alexandra Tkachuk, and Svetlana Ivanova. "New Monocrystals with Low Phonon Energy for Mid-IR Lasers." In NATO Science for Peace and Security Series B: Physics and Biophysics, 3–65. Dordrecht: Springer Netherlands, 2008. http://dx.doi.org/10.1007/978-1-4020-6463-0_1.

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9

Kita, T., K. Yamashita, T. Nishino, Y. Wang, and K. Murase. "Energy relaxation by phonon scattering in long-range ordered (Al0.5Ga0.5)0.5In0.5P." In Springer Proceedings in Physics, 218–19. Berlin, Heidelberg: Springer Berlin Heidelberg, 2001. http://dx.doi.org/10.1007/978-3-642-59484-7_97.

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10

Torres, Clivia M. Sotomayor. "Energy Relaxation in Quantum Dots: Recent Developments on the Phonon Bottleneck." In Hot Carriers in Semiconductors, 287–92. Boston, MA: Springer US, 1996. http://dx.doi.org/10.1007/978-1-4613-0401-2_66.

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Тези доповідей конференцій з теми "Phonon energy":

1

Pop, Eric. "Electron-Phonon Interaction and Joule Heating in Nanostructures." In ASME 2008 3rd Energy Nanotechnology International Conference collocated with the Heat Transfer, Fluids Engineering, and Energy Sustainability Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/enic2008-53050.

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The electron-phonon energy dissipation bottleneck is examined in silicon and carbon nanoscale devices. Monte Carlo simulations of Joule heating are used to investigate the spectrum of phonon emission in bulk and strained silicon. The generated phonon distributions are highly non-uniform in energy and momentum, although they can be approximately grouped into one third acoustic (AC) and two thirds optical phonons (OP) at high electric fields. The phonon dissipation is markedly different in strained silicon at low electric fields, where certain relaxation mechanisms are blocked by scattering selection rules. In very short (∼10 nm) silicon devices, electron and phonon transport is quasi-ballistic, and the heat generation domain is much displaced from the active device region, into the contact electrodes. The electron-phonon bottleneck is more severe in carbon nanotubes, where the optical phonon energy is three times higher than in silicon, and the electron-OP interaction is entirely dominant at high fields. Thus, persistent hot optical phonons are easily generated under Joule heating in single-walled carbon nanotubes suspended between two electrodes, in vacuum. This leads to negative differential conductance at high bias, light emission, and eventual breakdown. Conversely, optical and electrical measurements on such nanotubes can be used to gauge their thermal properties. The hot optical phonon effects appear less pronounced in suspended nanotubes immersed in an ambient gas, suggesting that phonons find relaxation pathways with the vibrational modes of the ambient gas molecules. Finally, hot optical phonons are least pronounced for carbon nanotube devices lying on dielectrics, where the OP modes can couple into the vibrational modes of the substrate. Such measurements and modeling suggest very interesting, non-equilibrium coupling between electrons and phonons in solid-state devices at nanometer length and picoseconds time scales.
2

Wu, Alexander Q., and Xianfan Xu. "Ultrafast Diagnostics of Coherent Phonon Excitation and Energy Transfer." In ASME 2006 International Mechanical Engineering Congress and Exposition. ASMEDC, 2006. http://dx.doi.org/10.1115/imece2006-13773.

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Time resolved reflectivity of bismuth thin film evaporated on a silicon substrate is measured by an 80 femtosecond (fs) laser at a center wavelength of 800 nm. The reflectivity data reveal that coherent optical phonons (A1g) near 2.9 THz (1 THz = 1012 Hz) are excited by the 80 fs laser pulses. Analyses of the reflectivity data reveal key parameters related to electron and phonon dynamics, including phonon excitation and de-phasing and electron-phonon energy coupling. It is also found that the phonon frequency peaks are red-shifted and broadened at higher laser fluences.
3

Gu, Yunfeng, Zhonghua Ni, Minhua Chen, Kedong Bi, and Yunfei Chen. "The Phonon Thermal Conductivity of a Single-Layer Graphene From Complete Phonon Dispersion Relations." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-39645.

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In this paper, the phonon scattering mechanisms of a single layer graphene are investigated based on the complete phonon dispersion relations. According to the selection rules that a phonon scattering process should obey the energy and momentum conservation conditions, the relaxation rates of combing and splitting Umklapp processes can be calculated by integrating the intersection lines between different phonon mode surfaces in the phonon dispersion relation space. The dependence of the relaxation rates on the wave vector directions is presented with a three dimensional surfaces over the first Brillion zone. It is found that the reason for the optical phonons contributing a little to heat transfer is attributed to the strong Umklapp processes but not to their low group velocities. The combing Umklapp scattering processes involved by the optical phonons mainly decrease the acoustic phonon thermal conductivity, while the splitting Umklapp scattering processes of the optical phonons mainly restrict heat conduction by the optical phonons themselves. Neglecting the splitting processes, the optical phonons can contribute more energy than that carried by the acoustic phonons. Based on the calculated phonon relaxation time, the thermal conductivities contributed from different mode phonons can be evaluated. At low temperatures, both longitudinal and in-plane transverse acoustic phonon thermal conductivities have T2 temperature dependence, and the out-of-plane transverse acoustic phonon thermal conductivity is proportion to T3/2. At room temperature, the calculated thermal conductivity is on the order of a few thousands W/m.K depending on the sample size and the edge roughness, which is in agreement with the recently measured data.
4

Yen, William M., and William M. Dennis. "Phonon spectroscopy and phonon-induced energy transfer in solids." In Excitonic Processes in Condensed Matter: International Conference, edited by Jai Singh. SPIE, 1995. http://dx.doi.org/10.1117/12.200964.

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5

Yang, C. H., and S. A. Lyon. "Fast energy relaxation of hot electrons in bulk GaAs and multi-quantum wells." In International Conference on Ultrafast Phenomena. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/up.1986.tue5.

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The relaxation of photo-excited hot carriers in GaAs is difficult to measure because of the time scale involved is so short. Generally the hot electrons relax at low lattice temperatures in three stages. First, hot carriers thermalize through electron-electron and LO phonon scattering and fall to an energy range where the electron population can be described by Fermi distribution (electron temperature, Te, greater than lattice temperature). Then this quasi-equilibrium distribution cools through the emission of LO phonons by the electrons in the high energy tail. After the carrier temperature is below about 30K, acoustic phonon emission slowly cools the distribution to the lattice temperature. Our experiment measures the average thermalization rate during the first stage of this process.
6

Miller, John, Wanyoung Jang, and Chris Dames. "Thermal Rectification by Ballistic Phonons." In ASME 2008 3rd Energy Nanotechnology International Conference collocated with the Heat Transfer, Fluids Engineering, and Energy Sustainability Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/enic2008-53064.

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In analogy to the asymmetric transport of electricity in a familiar electrical diode, a thermal rectifier transports heat more favorably in one direction than in the reverse direction. One approach to thermal rectification is asymmetric scattering of phonons and/or electrons, similar to suggestions in the literature for a sawtooth nanowire [1] or 2-dimensional electron gas with triangular scatterers [2]. To model the asymmetric heat transport in such nanostructures, we have used phonon ray-tracing, focusing on characteristic lengths that are small compared to the mean free path of phonons in bulk. To calculate the heat transfer we use a transmission-based (Landauer-Buttiker) method. The system geometry is described by a four-dimensional transfer function that depends on the position and angle of phonon emission and absorption from each of two contacts. At small temperature gradients, the phonon distribution function is very close to the usual isotropic equilibrium (Bose-Einstein) distribution, and there is no thermal rectification. In contrast, at large temperature gradients, the anisotropy in the phonon distribution function becomes significant, and the resulting heat flux vs. temperature curve (analogous to I-V curve of a diode) reveals large thermal rectification.
7

Turney, J. E., A. J. H. McGaughey, and C. H. Amon. "Argon Thermal Conductivity by Anharmonic Lattice Dynamics Calculations." In ASME 2008 Heat Transfer Summer Conference collocated with the Fluids Engineering, Energy Sustainability, and 3rd Energy Nanotechnology Conferences. ASMEDC, 2008. http://dx.doi.org/10.1115/ht2008-56146.

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Lattice dynamics calculations are used to investigate thermal transport in the face-centered cubic Lennard-Jones (LJ) argon crystal between temperatures of 20 and 80 K. First, quasi-harmonic lattice dynamics calculations are used to find the frequencies and mode shapes of non-interacting phonons [1]. This information is then used as input for anharmonic lattice dynamics calculations. Anharmonic lattice dynamics is a means of computing the frequency shift and lifetime of each phonon mode due to interactions with other phonons [2]. The phonon frequencies, group velocities, and lifetimes, determined with the lattice dynamics methods, are then used to compute the thermal conductivity. The thermal conductivities predicted by the lattice dynamics methods are compared to predictions from molecular dynamics simulations. The two methods are found to agree well at low temperature but diverge at higher temperatures (i.e., near the melting point). The properties of individual phonon modes are used to identify the modes that dominate thermal transport.
8

Zuckerman, Neil, and Jennifer R. Lukes. "Atomistic Visualization of Ballistic Phonon Transport." In ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference collocated with the ASME 2007 InterPACK Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ht2007-32674.

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Heat transfer in solid materials at short time scales, short length scales, and low temperatures is governed by the transport of ballistic phonons. In anisotropic crystals, the energy carried by these phonons is strongly channeled into well-defined directions in a phenomenon known as phonon focusing. Presented here is a new molecular dynamics simulation approach for visualizing acoustic phonon focusing in anisotropic crystals. An advantage of this approach over experimental phonon imaging techniques is that it allows examination of phonon propagation at selected modes and frequencies. The spatial, mode, and frequency dependence of ballistic energy transport gained with this approach will be useful for understanding heat transfer issues in high frequency electronics and short time scale laser-material interactions.
9

Medlar, Michael P., and Edward C. Hensel. "Electron-Phonon Interactions for Nanoscale Energy Transport Simulations in Semiconductor Devices." In ASME 2023 Heat Transfer Summer Conference collocated with the ASME 2023 17th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2023. http://dx.doi.org/10.1115/ht2023-106873.

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Abstract An ideal semiconductor device would permit unimpeded flow of electrons from its source to its drain in a fashion that can be switched on and off by its gate at high frequency. Electron flow through real semiconductor devices is impeded by interactions with the crystalline structure of the material. Electrons which interact with the crystal may generate phonons which manifest as thermal energy generation and degrade real device performance from its ideal limit. Accurate simulation of electron-phonon interactions cannot rely on the traditional continuum assumption because of the reduced length and time scales of modern semiconductor devices. Allowable electron-phonon interactions are constrained by the conservation of energy and momentum. Direct enforcement of the conservation laws is achieved through computation of an interaction table that contains thousands of rows each of which representing a conservative interaction. The rows represent both phonon and electron creation and annihilation. The electron and phonon wavevector space is discretized into 65,856 elements and the table is computed by searching the discretized wavevector space for electron and phonon states that first satisfy the conservation of momentum. Subsequently, these states are compared against the conservation of energy using the phonon and electron dispersion relations. Anisotropic phonon dispersion relations were calculated using a second nearest neighbor lattice dynamics approach with interatomic force constants from Density Functional Theory. Electron dispersion relations were computed using an empirical pseudopotential approach. This method was demonstrated for computation of electron-phonon interactions in silicon, resulting in an initial interaction table containing approximately 58,000 interactions. Computation of the electron energies associated with the first conduction band in an anisotropic manner illustrate reasonable agreement with published work. The interaction densities show similar functionality relative to the electron-phonon interaction rate predictions and phonon generation rates from published literature. The interaction table directly enforces the conservation laws on all electron-phonon interactions and the interaction table approach can be used for high fidelity electron-phonon simulations to quantify the mechanism, rate, and location of thermal losses arising at the nanoscale.
10

Wang, Yan, and Xiulin Ruan. "An Evaluation of Energy Transfer Pathways in Thermal Transport Across Solid/Solid Interfaces." In ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/ht2013-17297.

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Анотація:
Thermal transport across solid/solid interfaces has been extensively studied, but heat transfer pathways other than phonon transmission and electron-phonon nonequilibrium in the metal were usually neglected. In this work, we aim to build a general and unified model including both the above transport channels and others such as electron transmission and electron-interface coupling. For a general solid/solid system with electrons and phonons existing on both sides, an analytical solution to the interfacial thermal resistance is obtained. We show that the relative contribution from different transport channels depends on both the local condition at the interface and the bulk properties of each side of the interface. We find that for a metallic thin film deposited on a semiconductor substrate, the contribution of electron transmission to thermal transport is negligible when the semiconductor is not heavily doped even though the electronic interfacial thermal boundary resistance can be lower than the phononic counterpart at high temperatures. In contrast, the electron-interface channel plays an important role in the intrinsic to low-doped regime, where substrate phonons can remove heat efficiently from the interface.

Звіти організацій з теми "Phonon energy":

1

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2

Brodsky, Stanley J. High-Energy QCD Asymptotics of Photon--Photon Collisions. Office of Scientific and Technical Information (OSTI), July 2002. http://dx.doi.org/10.2172/799968.

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3

Brodsky, S. High Energy Photon-Photon Collisions at a Linear Collider. Office of Scientific and Technical Information (OSTI), April 2004. http://dx.doi.org/10.2172/826868.

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4

Abbasabadi, A., A. Devoto, D. A. Dicus, and W. W. Repko. High energy photon-neutrino interactions. Office of Scientific and Technical Information (OSTI), July 1998. http://dx.doi.org/10.2172/639760.

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5

Hussain, Zahid, Lori Tamura, Howard Padmore, Bob Schoenlein, and Sue Bailey. Photon Science for Renewable Energy. Office of Scientific and Technical Information (OSTI), March 2010. http://dx.doi.org/10.2172/983097.

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6

Adams, Terry R., Travis John Trahan, Jeremy Ed Sweezy, Steven Douglas Nolen, Henry Grady Hughes, Lori A. Pritchett-Sheats, and Christopher John Werner. Continuous Energy Photon Transport Implementation in MCATK. Office of Scientific and Technical Information (OSTI), October 2016. http://dx.doi.org/10.2172/1330646.

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7

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8

Kensek, Ronald, Harold Hjalmarson, Rudolph Magyar, Robert Bondi, and Martin Crawford. LDRD project 151362 : low energy electron-photon transport. Office of Scientific and Technical Information (OSTI), September 2013. http://dx.doi.org/10.2172/1096488.

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9

Gollapinni, Sowjanya, Georgia Karagiorgi, Mark Lonegran, William Louis, Richard Van De Water, Andrew Mogan, Gray Yarbrough, Wei Tang, Collaboration MicroBooNE, and Rob Fine. The MicroBooNE Single-Photon Low-Energy Excess Search. Office of Scientific and Technical Information (OSTI), October 2020. http://dx.doi.org/10.2172/1699415.

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10

Holtmann, Erich Nielsen. Big-bang nucleosynthesis with high-energy photon injection. Office of Scientific and Technical Information (OSTI), May 1999. http://dx.doi.org/10.2172/753050.

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