Articoli di riviste: "1D quantum gas"

1

Guan, Xiwen. "Critical phenomena in one dimension from a Bethe ansatz perspective". International Journal of Modern Physics B 28, n. 24 (5 agosto 2014): 1430015. http://dx.doi.org/10.1142/s0217979214300151.

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This article briefly reviews recent theoretical developments in quantum critical phenomena in one-dimensional (1D) integrable quantum gases of cold atoms. We present a discussion on quantum phase transitions, universal thermodynamics, scaling functions and correlations for a few prototypical exactly solved models, such as the Lieb–Liniger Bose gas, the spin-1 Bose gas with antiferromagnetic spin-spin interaction, the two-component interacting Fermi gas as well as spin-3/2 Fermi gases. We demonstrate that their corresponding Bethe ansatz solutions provide a precise way to understand quantum many-body physics, such as quantum criticality, Luttinger liquids (LLs), the Wilson ratio, Tan's Contact, etc. These theoretical developments give rise to a physical perspective using integrability for uncovering experimentally testable phenomena in systems of interacting bosonic and fermonic ultracold atoms confined to 1D.

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Laburthe Tolra, B., K. M. O'Hara, J. H. Huckans, M. Anderlini, J. V. Porto, S. L. Rolston e W. D. Phillips. "Study of a 1D interacting quantum Bose gas". Journal de Physique IV (Proceedings) 116 (ottobre 2004): 227–32. http://dx.doi.org/10.1051/jp4:2004116010.

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Sato, Jun, Rina Kanamoto, Eriko Kaminishi e Tetsuo Deguchi. "Quantum states of dark solitons in the 1D Bose gas". New Journal of Physics 18, n. 7 (11 luglio 2016): 075008. http://dx.doi.org/10.1088/1367-2630/18/7/075008.

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Guan, Xi-Wen, e Feng He. "Professor Chen Ping Yang’s early significant contributions to mathematical physics". International Journal of Modern Physics B 33, n. 06 (10 marzo 2019): 1930002. http://dx.doi.org/10.1142/s0217979219300020.

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In the 60s Professor Chen Ping Yang with Professor Chen Ning Yang published several seminal papers on the study of Bethe’s hypothesis for various problems of physics. The works on the lattice gas model, critical behavior in liquid–gas transition, the one-dimensional (1D) Heisenberg spin chain, and the thermodynamics of 1D delta-function interacting bosons are significantly important and influential in the fields of mathematical physics and statistical mechanics. In particular, the work on the 1D Heisenberg spin chain led to subsequent developments in many problems using Bethe’s hypothesis. The method which Yang and Yang proposed to treat the thermodynamics of the 1D system of bosons with a delta-function interaction leads to significant applications in a wide range of problems in quantum statistical mechanics. The Yang and Yang thermodynamics has found beautiful experimental verifications in recent years.

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Kaminishi, Eriko, Jun Sato e Tetsuo Deguchi. "Recurrence Time in the Quantum Dynamics of the 1D Bose Gas". Journal of the Physical Society of Japan 84, n. 6 (15 giugno 2015): 064002. http://dx.doi.org/10.7566/jpsj.84.064002.

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Kinjo, Kayo, Eriko Kaminishi, Takashi Mori, Jun Sato, Rina Kanamoto e Tetsuo Deguchi. "Quantum Dark Solitons in the 1D Bose Gas: From Single to Double Dark-Solitons". Universe 8, n. 1 (21 dicembre 2021): 2. http://dx.doi.org/10.3390/universe8010002.

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We study quantum double dark-solitons, which give pairs of notches in the density profiles, by constructing corresponding quantum states in the Lieb–Liniger model for the one-dimensional Bose gas. Here, we expect that the Gross–Pitaevskii (GP) equation should play a central role in the long distance mean-field behavior of the 1D Bose gas. We first introduce novel quantum states of a single dark soliton with a nonzero winding number. We show them by exactly evaluating not only the density profile but also the profiles of the square amplitude and phase of the matrix element of the field operator between the N-particle and (N−1)-particle states. For elliptic double dark-solitons, the density and phase profiles of the corresponding states almost perfectly agree with those of the classical solutions, respectively, in the weak coupling regime. We then show that the scheme of the mean-field product state is quite effective for the quantum states of double dark solitons. Assigning the ideal Gaussian weights to a sum of the excited states with two particle-hole excitations, we obtain double dark-solitons of distinct narrow notches with different depths. We suggest that the mean-field product state should be well approximated by the ideal Gaussian weighted sum of the low excited states with a pair of particle-hole excitations. The results of double dark-solitons should be fundamental and useful for constructing quantum multiple dark-solitons.

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Marino, E. C., e Flávio I. Takakura. "Massive Quantum Vortex Excitations in a Pure Gauge Abelian Theory in 2 + 1D". International Journal of Modern Physics A 12, n. 23 (20 settembre 1997): 4155–65. http://dx.doi.org/10.1142/s0217751x97002279.

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We introduce and study a pure gauge Abelian theory in 2 + 1D in which massive quantum vortex states do exist in the spectrum of excitations. This theory can be mapped in a three-dimensional gas of point particles with a logarithmic interaction, in the grand-canonical ensemble. We claim that this theory is the 2 + 1D analog of the sine–Gordon, the massive vortices being the counterparts of sine–Gordon solitons. We show that a symmetry breaking, order parameter, similar to the vacuum expectation value of a Higgs field does exist.

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Bouneb, I., e F. Kerrour. "Nanometric Modelization of Gas Structure, Multidimensional using COMSOL Software". International Journal of Electrical and Computer Engineering (IJECE) 8, n. 4 (1 agosto 2018): 2014. http://dx.doi.org/10.11591/ijece.v8i4.pp2014-2020.

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In structures with GaAs, which are the structures most used, because of their physical and electronic proprieties, nevertheless seems a compromise between the increase of doping and reduced mobility. The use of quantum hetero structures can overcome this limitation by creating a 2D carrier gas. Using the COMSOL software this work present three models: the first model computes the electronic states for the heterojunction AlGaAs/GaAs in 1D dimension, the second model computes the electronic states for the heterojunction AlGaAs/GaAs but in 2D dimension (nanowire) and the third model we permitted the study of this hetero junction (steep) wich inevitably involves the resolution of the system of equations Schrödinger-Poisson due to quantum effects that occur at the interface. The validity of this model can be effectuated with a comparison of our results with the result of different models developed in the literature of the related work, from this point of view the validity of our model is confirmed.

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Pan, Jun, Hao Shen e Sanjay Mathur. "One-Dimensional SnO2Nanostructures: Synthesis and Applications". Journal of Nanotechnology 2012 (2012): 1–12. http://dx.doi.org/10.1155/2012/917320.

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Nanoscale semiconducting materials such as quantum dots (0-dimensional) and one-dimensional (1D) structures, like nanowires, nanobelts, and nanotubes, have gained tremendous attention within the past decade. Among the variety of 1D nanostructures, tin oxide (SnO2) semiconducting nanostructures are particularly interesting because of their promising applications in optoelectronic and electronic devices due to both good conductivity and transparence in the visible region. This article provides a comprehensive review of the recent research activities that focus on the rational synthesis and unique applications of 1D SnO2nanostructures and their optical and electrical properties. We begin with the rational design and synthesis of 1D SnO2nanostructures, such as nanotubes, nanowires, nanobelts, and some heterogeneous nanostructures, and then highlight a range of applications (e.g., gas sensor, lithium-ion batteries, and nanophotonics) associated with them. Finally, the review is concluded with some perspectives with respect to future research on 1D SnO2nanostructures.

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Kaminishi, Eriko, Jun Sato e Tetsuo Deguchi. "Exact quantum dynamics of yrast states in the finite 1D Bose gas". Journal of Physics: Conference Series 497 (9 aprile 2014): 012030. http://dx.doi.org/10.1088/1742-6596/497/1/012030.

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Lafont, Fabien, Amir Rosenblatt, Moty Heiblum e Vladimir Umansky. "Counter-propagating charge transport in the quantum Hall effect regime". Science 363, n. 6422 (3 gennaio 2019): 54–57. http://dx.doi.org/10.1126/science.aar3766.

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The quantum Hall effect, observed in a two-dimensional (2D) electron gas subjected to a perpendicular magnetic field, imposes a 1D-like chiral, downstream, transport of charge carriers along the sample edges. Although this picture remains valid for electrons and Laughlin’s fractional quasiparticles, it no longer holds for quasiparticles in the so-called hole-conjugate states. These states are expected, when disorder and interactions are weak, to harbor upstream charge modes. However, so far, charge currents were observed to flow exclusively downstream in the quantum Hall regime. Studying the canonical spin-polarized and spin-unpolarized v = 2/3 hole-like states in GaAs-AlGaAs heterostructures, we observed a significant upstream charge current at short propagation distances in the spin unpolarized state.

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Mann, Joshua, Gerard Lawler e James Rosenzweig. "1D Quantum Simulations of Electron Rescattering with Metallic Nanoblades". Instruments 3, n. 4 (5 novembre 2019): 59. http://dx.doi.org/10.3390/instruments3040059.

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Electron rescattering has been well studied and simulated for cases with ponderomotive energies of the quasi-free electrons, derived from laser–gas and laser–surface interactions, lower than 50 eV. However, with advents in longer wavelengths and laser field enhancement metallic surfaces, previous simulations no longer suffice to describe more recent strong field and high yield experiments. We present a brief introduction to and some of the theoretical and empirical background of electron rescattering emissions from a metal. We set upon using the Jellium potential with a shielded atomic surface potential to model the metal. We then explore how the electron energy spectra are obtained in the quantum simulation, which is performed using a custom computationally intensive time-dependent Schrödinger equation solver via the Crank–Nicolson method. Finally, we discuss the results of the simulation and examine the effects of the incident laser’s wavelength, peak electric field strength, and field penetration on electron spectra and yields. Future simulations will investigate a more accurate density functional theory metallic model with a system of several non-interacting electrons. Eventually, we will move to a full time-dependent density functional theory approach.

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Hou, Ji-Xuan, Li-Ming Si e Da-Bao Yang. "Low-lying Collective Modes of a 1D Dipolar Quantum Gas in an Anharmonic Trap". Brazilian Journal of Physics 47, n. 4 (20 giugno 2017): 377–81. http://dx.doi.org/10.1007/s13538-017-0506-z.

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14

Prokes, S. M., e Kang L. Wang. "Novel Methods of Nanoscale Wire Formation". MRS Bulletin 24, n. 8 (agosto 1999): 13–19. http://dx.doi.org/10.1557/s0883769400052842.

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In recent years, tremendous interest has been generated in the fabrication and characterization of nanoscale structures such as quantum dots and wires. For example, there is interest in the electronic, magnetic, mechanical, and chemical properties of materials with reduced dimensions. In the case of nanoscale semiconductors, quantum effects are expected to play an increasingly prominent role in the physics of nanostructures, and a new class of electronic and optoelectronic devices may be possible. In addition to new and interesting physics, the formation and characterization of nanoscale magnetic structures could result in higher-density storage capacity in hard disks and optical-recording media. Likewise, phonon confinement leads to a drastic reduction of thermal conductivity and can be used to improve the performance of thermoelectric devices.In 1980, H. Sakaki predicted theoretically that quantum wires may have applications in high-performance transport devices, due to their sawtoothlike density of states (E1/2), where E is the electron energy. Since then, most quantum wires have been made by fabricating a gratinglike gate on top of a two-dimensional (2D) electron gas contained in a semiconductor heterojunction or in metal-oxide-semiconductor structures. By applying a negative gate voltage to the system, its structure can be changed from a 2D to a one-dimensional (1D) regime, where electron confinement is achieved by an electrostatic confining potential. It was not until recently that “physical” semiconductor quantum wires with the demonstrated 1D confinement by physical boundaries began to be fabricated.

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15

CONSTANTINIDIS, C. P., F. TOPPAN e F. P. DEVECCHI. "TWO-DIMENSIONAL N=1,2 SUPERSYMMETRIC CHIRAL AND DUAL MODELS". Modern Physics Letters A 13, n. 26 (30 agosto 1998): 2095–109. http://dx.doi.org/10.1142/s0217732398002217.

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Two-dimensional N=1,2 supersymmetric chiral models and their dual extensions are introduced and canonically quantized. Working within a superspace formalism, the non-manifest invariance under 2D-super-Poincaré transformations is proven. The N=1,2 super-Virasoro algebras are recovered as current algebras. The non-anomalous quantum invariances under 1D-superdiffeomorphisms (for chiral models) and N=1,2 superconformal transformations (for dual models) are shown to be a consequence of an N=1,2 super-Coulomb gas representation.

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Kovalenko, Konstantin L., Sergei I. Kozlovskiy, Nicolai N. Sharan e Eugeniy F. Venger. "Bulk plasmon-limited mobility in semiconductors: from bulk to nanowires". Journal of Physics: Condensed Matter 35, n. 47 (30 agosto 2023): 475303. http://dx.doi.org/10.1088/1361-648x/acef88.

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Abstract Analytical expressions are obtained for the low-field mobility in semiconductors for scattering of three-dimensional (3D), two-dimensional (2D), and one-dimensional (1D) charged carriers by bulk plasmons. The consideration is based on the quantum kinetic equation and model distribution function in form of a shifted Fermi distribution and includes calculations of the dielectric function of 3D, 2D and 1D carriers in the random phase approximation. The resulting analytical expressions give dependences of the plasmon limited mobility on the dimensionality of charge carrier system, their density, effective mass, temperature and confining dimensions. The plasmon limited mobility decreases as the dimensionality of the electron gas D decreases. The physical reason for this is an increase in the absolute value of the cutoff vector with a decrease in D. Comparison of our calculations with known experimental data shows that relative contribution of the electron–plasmon scattering to total mobility reaches a maximum in the temperature range 10–100 K and can be a few percent in bulk crystals, ten of percent in quantum wells, and is close to the experimental values in nanowires. A noticeable effect of the scattering 3D, 2D and 1D electrons by bulk plasmons on mobility is expected in semiconductors with a sufficiently high mobility of more than 105 cm2 V−1 s.

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Kovalenko, Konstantin L., Sergei I. Kozlovskiy, Nicolai N. Sharan e Eugeniy F. Venger. "Low field mobility in bulk GaN and its ternary AlGaN/GaN compounds (quantum kinetic approach)". Journal of Physics: Condensed Matter 36, n. 32 (13 maggio 2024): 325705. http://dx.doi.org/10.1088/1361-648x/ad44fb.

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Abstract Analytical expressions for the low-field mobility of charge carrier gases with three-(3D), two-(2D) and one-(1D) dimensionalities are obtained. Multi-ion ionized impurities scattering, acoustic and polar optic phonons are considered as scattering mechanisms. The calculated values of mobility are compared to known experimental data for bulk (3D) n-and p-type wurtzite, n-type zinc-blende GaN crystals and low dimensional (2D and 1D) ternary GaAlN compounds. The resulting analytical expressions give the dependences of mobility on dimensionality of charge carrier gas, its density, effective mass, temperature and confining dimensions. A comparison of the experimental and calculated temperature dependences of the mobility in bulk GaN crystals (3D) and in AlGaN/GaN nanowires (1D) shows that the mobility at T > 100 K is determined by the scattering of charge carriers by polar optical phonons with an energy of 91.2 meV. The temperature dependences of mobility in Al0.25Ga0.75N/GaN heterostructures (2D) at T > 100 K are in consistent with experiment for electron scattering by polar optical phonons with a noticeably higher energy of 160 meV. We associate this fact with the heterointerface, which according to well-known theoretical studies can change both the strength of electron polar optical phonons scattering and the energy of the phonons.

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MIRONOV, A., e A. ZABRODIN. "THE ASYMPTOTICS OF THE CORRELATION FUNCTIONS IN (1+1)d QUANTUM FIELD THEORY FROM FINITE SIZE EFFECTS IN CONFORMAL THEORIES". International Journal of Modern Physics A 07, n. 16 (30 giugno 1992): 3885–909. http://dx.doi.org/10.1142/s0217751x92001745.

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Using the finite-size effects, the scaling dimensions and correlation functions of the main operators in continuous and lattice models of 1d spinless Bose-gas with pairwise interaction of rather general form are obtained. The long-wave properties of these systems can be described by the Gaussian model with central charge c=1. The disorder operators of the extended Gaussian model are found to correspond to some nonlocal operators in the XXZ Heisenberg antiferromagnet. This same approach is applicable to fermionic systems. Scaling dimensions of operators and correlation functions in the systems of interacting Fermi-particles are obtained. We present a universal treatment for 1d systems of different kinds which is independent of the exact integrability and which gives universal expressions for critical exponents through the thermodynamic characteristics of the system.

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MA, YONG-LI, e HAICHEN ZHU. "A CLASS OF CLOSED SOLUTIONS FOR THE BOGOLIUBOV EXCITATIONS ON SMOOTH GROUND STATE OF A TRAPPED BOSE–EINSTEIN CONDENSATE". Modern Physics Letters B 19, n. 15 (30 giugno 2005): 713–20. http://dx.doi.org/10.1142/s0217984905008670.

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Bogoliubov–de Gennes equations (BdGEs) for collective excitations from a trapped Bose–Einstein condensate described by a spatially smooth ground-state wavefunction can be treated analytically. A new class of closed solutions for the BdGEs is obtained for the one-dimensional (1D) and 3D spherically harmonic traps. The solutions of zero-energy mode of the BdGEs are also provided. The eigenfunctions of the excitations consist of zero-energy mode, zero-quantum-number mode and entire excitation modes when the approximate ground state is a background Bose gas sea.

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Tan, Yunzhi, Qiang Zhu, Bing Wang, Jingran Shi, Dezhi Xiong e Baolong Lyu. "Density–Density Correlation Spectra of Ultracold Bosonic Gas Released from a Deep 1D Optical Lattice". Entropy 26, n. 10 (10 ottobre 2024): 854. http://dx.doi.org/10.3390/e26100854.

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Density–density correlation analysis is a convenient diagnostic tool to reveal the hidden order in the strongly correlated phases of ultracold atoms. We report on a study of the density–density correlations of ultracold bosonic atoms which were initially prepared in a Mott insulator (MI) state in one-dimensional optical lattices. For the atomic gases released from the deep optical lattice, we extracted the normalized density–density correlation function from the atomic density distributions of freely expanded atomic clouds. Periodic bunching peaks were observed in the density–density correlation spectra, as in the case of higher-dimensional lattices. Treating the bosonic gas within each lattice well as a subcondensate without quantum tunneling, we simulated the post-expansion density distribution along the direction of the 1D lattice, and the calculated density–density correlation spectra agreed with our experimental observations.

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Oganesov, Armen, George Vahala, Linda Vahala, Jeffrey Yepez, Min Soe e Bo Zhang. "Unitary quantum lattice gas algorithm generated from the Dirac collision operator for 1D soliton–soliton collisions". Radiation Effects and Defects in Solids 170, n. 1 (2 gennaio 2015): 55–64. http://dx.doi.org/10.1080/10420150.2014.988625.

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Hashimoto, Kazunari, Kazuki Kanki, Savannah Garmon, Satoshi Tanaka e Tomio Petrosky. "On the effect of exceptional points in the Liouvillian dynamics of a 1D quantum Lorentz gas". Progress of Theoretical and Experimental Physics 2016, n. 5 (maggio 2016): 053A02. http://dx.doi.org/10.1093/ptep/ptw039.

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Stasyuk, I., R. Stetsiv e O. Farenyuk. "Low-frequency dynamics of 1d quantum lattice gas: the case of local potential with double wells". Mathematical Modeling and Computing 5, n. 2 (1 dicembre 2018): 235–41. http://dx.doi.org/10.23939/mmc2018.02.235.

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Hermann, Sascha, Simon Böttger e Martin Hartmann. "(Invited) Suspended 1D/2D Nanomaterials: Progress on a Waferlevel Technology and Applications". ECS Meeting Abstracts MA2023-02, n. 30 (22 dicembre 2023): 1530. http://dx.doi.org/10.1149/ma2023-02301530mtgabs.

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The use of 1D and 2D nanomaterials in emerging electronics and sensor technologies is becoming increasingly important due to their unique properties. Here we would like to highlight a scalable process for suspended nanomaterials that provides additional scope for the development of device properties that can be used in advanced concepts ranging from molecular sensing to quantum applications [1]. For example those applications benefit from arrangements as CNT-based nanoresonators with extremely high quality factors [2] usable for quantum bits with long coherence time [3] or suspended sensing nanomaterials for ultra-low power and extremely sensitive gas sensors [4]. Moreover, straining allows to tune intrinsic physical properties of nanomaterials. Thus, the strain-dependence of the band gap (e.g. CNTs <100meV/% [5], MoS2 ~60meV/% [6],) paves the way for integrated-, highly-efficient-, and tunable light sources for on-chip spectrometry in the context of photonic integrated circuits (PICs), as recently reviewed in [7]. Our technological solution to manufacture suspended nanomaterials is aligned with established semiconductor processing chains on 200 mm wafer level and is developed to be modular integrable and compatible with MEMS, MEOMS or CMOS technologies [8]. Along the process chain, we demonstrate wafer-validated deposition processes for semiconducting CNT films which properties can be adjusted with respect to density and even alignment. In particular, for straining aligned CNTs as well as any transferable 2D nanomaterial, we implemented a stressed functional SiO2/SiN layer stack arranged on embedded sacrificial Cu-structures on the wafer surface. After contacting of the nanomaterial and release of sacrificial elements, stressed layers relax, strain and suspend the nanomaterial. This surface engineering approach greatly simplifies the introduction of strain into nanomaterials and makes it accessible for arbitrary device numbers on wafers as well as for monolithic 3D electronic concepts. Unique features include in-plane strains that are applicable in multiaxial directions and can be controlled by designing only two lithography planes. We show that devices with CNTs strained up to 1% determined from Raman spectral analysis, have a positive impact on sensor operation. We show application examples such as a mechanical stress sensor with extremely low on-set sensitivity. References [1] A. Baydin, F. Tay, J. Fan, M. Manjappa, W. Gao, and J. Kono, “Carbon Nanotube Devices for Quantum Technology,” Materials (Basel, Switzerland), vol. 15, no. 4, 2022. [2] J. Moser, A. Eichler, J. Güttinger, M. I. Dykman, and A. Bachtold, “Nanotube mechanical resonators with quality factors of up to 5 million,” Nature Nanotechnology, vol. 9, no. 12, pp. 1007–1011, 2014. [3] I. Khivrich and S. Ilani, “Nanotubes resound better,” Nature Nanotech, vol. 9, no. 12, pp. 963–964, 2014. [4] D.-H. Baek, J. Choi, and J. Kim, “Fabrication of suspended nanowires for highly sensitive gas sensing,” Sensors and Actuators B: Chemical, vol. 284, pp. 362–368, 2019. [5] L. Yang and J. Han, “Electronic structure of deformed carbon nanotubes,” Physical review letters, vol. 85, no. 1, pp. 154–157, 2000. [6] C. R. Zhu et al., “Strain tuning of optical emission energy and polarization in monolayer and bilayer MoS${}_{2}$,” Phys. Rev. B, vol. 88, no. 12, p. 121301, 2013. [7] M. Pandey, C. Pandey, R. Ahuja, and R. Kumar, “Straining techniques for strain engineering of 2D materials towards flexible straintronic applications,” Nano Energy, vol. 109, p. 108278, 2023. [8] S. Bottger, F. Dietz, M. Hartmann, N. Dahra, E. Kaulfersch, and S. Hermann, “Functional CMOS extension with integrated carbon nano devices,” in 2022 Smart Systems Integration (SSI): 27-28 April 2022, Grenoble, France, 2022, pp. 1–4.

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Djoufack, Z. I., A. Kenfack-Jiotsa e J. P. Nguenang. "Quantum signature of breathers in 1D ultracold bosons in optical lattices involving next-nearest neighbor interactions". International Journal of Modern Physics B 31, n. 20 (10 agosto 2017): 1750140. http://dx.doi.org/10.1142/s0217979217501405.

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The dynamics and the energy spectrum of an ultracold gas of bosonic atoms in an optical lattice can be described by a Bose–Hubbard model for which the system parameters can be controlled by laser light. We study by means of the perturbation theory in addition to the numerical diagonalization, the energy spectrum and the related features of the band structures of the ultracold bosons in optical lattices containing a few number of quanta interacting with next-nearest neighbor interactions (NNNI) modeled by the Bose–Hubbard Hamiltonian. The energy spectra of such system display the bound states signature, which are analyzed in the first Brillouin zone for different wave numbers. The finding, i.e., quantum breathers, shows that their probabilities’ weight depends on the wave vector. The influence of NNNI on both the probabilities’ amplitude and the correlation function is also realized in case of a system with a small number of sites, respectively.

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Lias, S., L. Aissaoui, M. Bouledroua e K. Alioua. "Quantum-mechanical transport properties of N+ (3P) and N+ (1D) ions in a neutral gas made of helium". Molecular Physics 118, n. 7 (26 agosto 2019): e1657601. http://dx.doi.org/10.1080/00268976.2019.1657601.

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Verma, Yogesh Kumar, Varun Mishra e Santosh Kumar Gupta. "A Physics-Based Analytical Model for MgZnO/ZnO HEMT". Journal of Circuits, Systems and Computers 29, n. 01 (26 marzo 2019): 2050009. http://dx.doi.org/10.1142/s0218126620500097.

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In this paper, a physics-based compact model is developed for novel MgZnO/ZnO high-electron-mobility transistor (HEMT). Poisson’s equation coupled with 1D Schrödinger equation is solved self-consistently in the triangular quantum well to derive an expression of two-dimensional electron gas (2DEG) density with respect to gate voltage at the heterointerface of barrier (MgZnO) and buffer (ZnO) layers. A compact mathematical framework has been devised further for the first time for ZnO-based HEMT to the best of our knowledge using the expression of 2DEG density to compute surface potential, gate charge, gate current, gate capacitance, current–voltage characteristics, output conductance, transconductance and cut-off frequency with respect to gate voltage and along with the drain–source output resistance [Formula: see text].

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Salinas-Torres, Angélica, Hugo Rojas, José J. Martínez, Diana Becerra e Juan-Carlos Castillo. "Synthesis, Characterization, and DFT Studies of N-(3,5-Bis(trifluoromethyl)benzyl)stearamide". Molbank 2021, n. 2 (25 maggio 2021): M1215. http://dx.doi.org/10.3390/m1215.

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The novel N-(3,5-bis(trifluoromethyl)benzyl)stearamide 3 was prepared in moderate yield by a solventless direct amidation reaction of stearic acid 1 with 3,5-bis(trifluoromethyl)benzylamine 2 at 140 °C for 24 h under metal- and catalyst-free conditions. This practical method was conducted in air without any special treatment or activation. The fatty acid amide 3 was fully characterized by IR, UV–Vis, 1D and 2D NMR spectroscopy, mass spectrometry, and elemental analysis. Moreover, molecular electrostatic potential studies, determination of quantum descriptors, fundamental vibrational frequencies, and intensity of vibrational bands were computed by density functional theory (DFT) using the B3LYP method with 6-311+G(d,p) basis set in gas phase. Simulation of the infrared spectrum using the results of these calculations led to good agreement with the observed spectral patterns.

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Dybowski, Michal P., Piotr Holowinski, Rafal Typek e Andrzej L. Dawidowicz. "Comprehensive analytical and structural characteristics of methyl 3,3-dimethyl-2-(1-(pent-4-en-1-yl)-1H-indazole-3-carboxamido)butanoate (MDMB-4en-PINACA)". Forensic Toxicology 39, n. 2 (1 aprile 2021): 481–92. http://dx.doi.org/10.1007/s11419-021-00573-y.

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Abstract Purpose The purpose of the study was to evaluate a complete analytical and structural characterization of methyl 3,3-dimethyl-2-(1-(pent-4-en-1-yl)-1H-indazole-3-carboxamido)butanoate (MDMB-4en-PINACA), a novel synthetic cannabinoid being the analogue of 5F-ADB. Methods The compound was analyzed by gas chromatography–mass spectrometry (GC–MS), high-resolution liquid chromatography–mass spectrometry (LC–MS), X-ray diffraction and spectroscopic methods, such as nuclear magnetic resonance (NMR) and Fourier-transform infrared (FTIR) spectroscopies. To derive MDMB-4en-PINACA molecular geometry and to assign infrared absorption bands, quantum calculations with the employment of density functional theory were also used. Results We present a wide range of chromatographic and spectroscopic data supported with theoretical calculations allowing to identify MDMB-4en-PINACA. Conclusions To our knowledge, this is the first report presenting a comprehensive analytical and structural characterization of MDMB-4en-PINACA obtained by 1D and 2D NMR, GC–MS, LC–MS(/MS), attenuated total reflection-FTIR spectroscopy, powder X-ray diffraction and quantum chemical calculations. The presented results not only broaden the knowledge about this psychoactive substance but also are useful for forensic and clinical purposes.

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Datta, S. "A Path Integral Monte Carlo Study of Anderson Localization in Cold Gases in the Presence of Disorder". International Journal of Computational Methods 13, n. 06 (2 novembre 2016): 1650032. http://dx.doi.org/10.1142/s0219876216500328.

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We revisit the problem of Anderson localization in a trapped Bose–Einstein condensate in 1D and 3D in a disordered potential, applying Quantum Monte Carlo technique because the disorder cannot be treated accurately in a perturbative way as even a small amount of disorder can produce dramatic changes in the physical properties of the system under investigation. Till date no unambiguous evidence of localization has been observed for matter waves in 3D. Matter waves made up of cold atoms are good candidates for such investigations. Simulations are performed for Rb gas in continuous space using canonical ensemble in the case of random and quasi-periodic potentials. To realize random and quasiperiodic potentials numerically we use speckle and bichromatic potentials, respectively. Owing to the high degree of control over the system parameters we specifically study the interplay of disorder and interaction in the system. A dilute Bose gas placed in a random environment falls into a fragmented localized state and the ergodicity (the repetitiveness of the wave function) is lost. An arbitrary Interaction can slowly overcome the effect of disorder and restore the ergodicity again. We observe that as the interaction strength increases, the wave functions become more and more delocalized. Since vanishing of Lyapunov exponent is only a necessary but not a sufficient condition for delocalization for probing the localization we calculate the mean square displacements as an alternative measure of localization. The path integral Monte Carlo technique in this paper numerically establishes the existing predictions of the scaling theory so far and paves a clear path for the further investigation of scaling theory to calculate more complicated properties like ‘critical exponents’ etc. in disordered quantum gases.

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Hoque, Md Ikram Ul, Andrew Gibson e Scott Donne. "(Digital Presentation) In-Situ Growth of SnO₂ Quantum Dots Onto Rgo for Supercapacitor Anodes". ECS Meeting Abstracts MA2022-02, n. 7 (9 ottobre 2022): 2518. http://dx.doi.org/10.1149/ma2022-0272518mtgabs.

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SnO2 has been studied as a negative electrode material for supercapacitors [1]. However, direct use of pure SnO2 is not suitable because of its poor electrical conductivity. In order to mitigate this issue, various materials have been incorporated with pure SnO2, including graphene which is most favourable because of its high electrical conductivity (106 S/cm) and surface area (2630 m2/g), leading to highly conductive nanocomposites, and consequently high electrode capacitance [2]. Therefore, there is a growing interest to develop SnO2 anchored graphene nanocomposites for fabrications of the supercapacitors negative electrode. In-situ growth and homogeneous distribution of the SnO2 on the graphene flakes are highly desirable, as the maximum interaction of SnO2 with the graphene would occur, resulting in high electrochemical performance. Besides, SnO2 quantum dots (TOQDs), which is a 0D material, exhibit remarkable efficiency towards supercapacitors, as they have more surface area compared to 1D, 2D and 3D nanomaterials. However, the fabrication of the TOQDs is still challenging [3]. Therefore, in-situ and homogeneous distribution of the TOQDs on graphene flakes could yield an attractive nanocomposite for the supercapacitor studies. We have synthesized TOQDs embedded reduced graphene oxide (RGO) flakes i.e.; (TOQDs/RGO) nanocomposite. A nanofluidic synthesis approach, which was applied to synthesis the TOQDs/RGO nanocomposite, leads to give in-situ and homogeneous growth of the SnO2-QDs on graphene flakes. The nanofluidic synthesis approach comprises the dropwise addition of a 1D-Sn(OH)4 nanofluid [4] with graphene oxide (GO) nanofluid [5] at room temperature followed by a stirring, sonication and freeze-drying process, respectively. Finally the freeze-dried sample was calcined at 600 °C for 6 hrs under nitrogen gas to obtain the TOQDs/RGO nanocomposite. The synthesis approach with prime electrochemical studies performance is illustrated in Figure 1. A three-electrode supercapacitor was individually constructed to perform cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). It is found that the developed TOQDs/RGO nanocomposite exhibits high capacitance. The results of these electrochemical studies revealed that the developed TOQDs/RGO nanocomposite can be used for high-performance supercapacitors. References: M. Hassan et al., Tin-Based Materials for Supercapacitor. Inorganic Nanomaterials for Supercapacitor Design, CRC Press: 2019; pp 119-131. Lakra et al., A mini-review: Graphene based composites for supercapacitor application. Inorg. Chem. Commun. 2021, 133, 108929. Inomata et al., Dendrimer-templated synthesis and characterization of tin oxide quantum dots deposited on a silica glass substrate. Chem. Mater. 2019, 31 (20), 8373-8382. I. U. Hoque et al., One-dimensional Sn (iv) hydroxide nanofluid toward nonlinear optical switching. Mater. Horiz. 2020, 7 (4), 1150-1159. A. Khan et al., Synthesis of graphene oxide nanofluid based micro-nano scale surfaces for high-performance nucleate boiling thermal management systems. Case Stud. Therm. Eng. 2021, 28, 101436. Figure 1

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Khan, Natalya, Fail Sultanov, Zhumabay Bakenov, Almagul Mentbayeva e Batukhan Tatykayev. "Easy Scalable Solid-State Synthesis of Highly Efficient Synergetic 2D/1D Micro/Nanostructured g-C₃N₄/MeS (Me=Cd, Mo) Photocatalysts for Organic Dye Degradation and Hydrogen Evolution". ECS Meeting Abstracts MA2024-01, n. 35 (9 agosto 2024): 1992. http://dx.doi.org/10.1149/ma2024-01351992mtgabs.

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The global reserves of oil, gas, and coal are acknowledged finite, and their consumption rates are increasing each year [1]. Following Fujishima’s groundbreaking discovery of photocatalytic water splitting using TiO2 electrodes in 1972 [2], photocatalysis technology gained recognition as a promising approach for renewable energy and environmental conservation [3]. Since that pivotal moment, significant advancements have been made in developing preparation methods for highly efficient photocatalysts, predominantly centered on semiconductors like metal oxides and sulfides [4]. In this study, we introduce effective synergistic photocatalysts, that utilize g-C3N4 and MeS (Me=Cd, Mo) semiconductors featuring a 2D/1D micro/nanostructure. Photocatalysts were successfully produced through solid-state method using planetary ball mill, where reaction of MeS formation occurs on the surface of g-C3N4. A comprehensive analysis of the binding energy of electrons of semiconductors was conducted to understand its impact on the photocatalytic activity of the prepared g-C3N4/MeS. The fabricated materials were used in the photodegradation of organic dyes and demonstrated remarkable efficacy. Regarding photocatalytic hydrogen evolution, the g-C3N4/CdS in conjunction with Pt co-catalyst, achieved a hydrogen evolution rate of up to 2254.54 μmol*h⁻¹ *g⁻¹, accompanied by apparent quantum efficiency of 2.0%. Acknowledgments This research was funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. АР13068426). References [1] E. V. Kondratenko, G. Mul, J. Baltrusaitis, G. O. Larrazábal, J. Pérez-Ramírez, Status and perspectives of CO2 conversion into fuels and chemicals by catalytic, photocatalytic and electrocatalytic processes, Energy & Environmental Science. 6 (2013) 3112–3135. https://doi.org/10.1039/C3EE41272E. [2] A. Fujishima, K. Honda, Electrochemical Photolysis of Water at a Semiconductor Electrode, Nature. 238 (1972) 37–38. https://doi.org/10.1038/238037a0. [3] M. Ni, M.K.H. Leung, D.Y.C. Leung, K. Sumathy, A review and recent developments in photocatalytic water-splitting using TiO2 for hydrogen production, Renewable and Sustainable Energy Reviews. 11 (2007) 401–425. https://doi.org/10.1016/j.rser.2005.01.009. [4] C. Acar, I. Dincer, G.F. Naterer, Review of photocatalytic water-splitting methods for sustainable hydrogen production, International Journal of Energy Research. 40 (2016) 1449–1473. https://doi.org/10.1002/er.3549.

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Hoque, Md Ikram Ul, Andrew Gibson e Scott Donne. "SnO₂-QDs/Rgo Nanocomposites for Lithium Ion Battery Anodes". ECS Meeting Abstracts MA2022-02, n. 7 (9 ottobre 2022): 2519. http://dx.doi.org/10.1149/ma2022-0272519mtgabs.

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SnO2 is one of the most efficient materials for lithium ion battery (LIBs) anodes as it can theoretically provide a reversible capacity of 790 mAh/g (graphite, 372 mAh/g) for alloying reaction with lithium ion [(i) SnO 2 + 4 Li+ + 4e - = 2Li 2 O + Sn, (ii) Sn + xLi+ + xe- = LixSn (0 ≤ x ≤ 4.4)] during charge-discharge process [1]. In addition, SnO2 shows lowest operating potentials (average charge and discharge potentials: 0.3 V and 0.5 V vs. Li/Li+, respectively) in comparison with other transition metal oxides, facilitating a higher energy density when a full cell is constructed [2]. However, two issues: (1) poor electric conductivity, and (2) high volume fluctuation during lithiation-delithiation process (about 200-300%), limit its direct use as the anode material. To bit these issues, various carbon materials are employed to load the SnO2 [3]. Graphene, a carbon allotrope, which possesses high electrical conductivity (106 s/cm), excellent mechanical flexibility (Young’s modulus up to 1.0 TPa) and high surface area (2630 m2/g) and in addition, lithium storage capacity of a single layer graphene is theoretically found to be 744 mAh/g. Consequently, graphene can be most suitable host to incorporate the SnO2 [3]. We have tailored SnO2 quantum dots (TOQDs) encapsulated reduced graphene oxide (RGO) nanocomposite (TOQDs/RGO) by in-situ growth of the TOQDs in the RGO flakes. A nanofluidic synthesis approach has been developed using 1D-Sn(OH)4 nanofluid [4] and graphene oxide (GO) nanofluid [5] as prim precursors for the homogeneous encapsulation of the TOQDs in RGO flakes. The 1D-Sn(OH)4 nanofluid was dropwise added to the graphene oxide (GO) nanofluid with continuous stirring. Then the resultant mixture was sonicated to get a nanofluidic mixture which was freeze-dried followed by calcination at 600 °C for 6 hrs under nitrogen gas. During these processes, in-situ growth of the TOQDs was proceeded on the RGO plane, leading to give their homogeneous distribution with encapsulation on the RGO plane. The cyclic voltammetry (CV) and glavanostatic charge-discharge (GCD) were performed on an Iviumstat Multichannel Potentiostat using a three-electrode cell and two-electrode cell, respectively. It is found that the developed TOQDs/RGO nanocomposite provides high reversible specific capacity with excellent rate capability. The results of these electrochemical studies implied that the developed TOQDs/RGO nanocomposite could be utilized for high-performance LIBs. References Lu et al., Porous SnO2/Graphene composites as anode materials for lithium-ion batteries: morphology control and performance improvement. Energy Fuels 2020, 34 (10), 13126-13136. Deng et al.,The developments of SnO2/graphene nanocomposites as anode materials for high performance lithium ion batteries: a review. J. Power Sources 2016, 304, 81-101. Han et al., Caging tin oxide in three-dimensional graphene networks for superior volumetric lithium storage. Nat. commun. 2018, 9 (1), 1-9. I. U. Hoque et al., One-dimensional Sn (iv) hydroxide nanofluid toward nonlinear optical switching. Mater. Horiz. 2020, 7 (4), 1150-1159. A. Khan et al., Synthesis of graphene oxide nanofluid based micro-nano scale surfaces for high-performance nucleate boiling thermal management systems. Case Stud. Therm. Eng. 2021, 28, 101436.

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RAJASHABALA, S., e R. KANNAN. "THEORETICAL INVESTIGATION ON THE OSCILLATOR STRENGTHS OF ELECTRIC DIPOLE TRANSITIONS IN A SPHERICAL QUANTUM DOT WITH HYDROGENIC DONOR IMPURITY". International Journal of Nanoscience 11, n. 02 (aprile 2012): 1250020. http://dx.doi.org/10.1142/s0219581x12500202.

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Dipole transition moment (DTM) of a hydrogenic donor in a spherical quantum dot of GaAs – Ga 1-x Al x As system with finite barrier confinement is obtained. The variational approach within the effective mass approximation is used as the framework for the calculation of donor ionization energy for a few excited states in quantum dot. Calculations of the DTM of an on-center shallow donor hydrogenic impurity in a GaAs quantum dot under hydrostatic pressure are presented. A linear increase in the DTM has been observed, when the dot radius increases from 2 nm to 100 nm. The important conclusions arrived at are (i) ionization energy increases and attains a maximum value occurring for a dot radius of 5 nm, after which the ionization energy decreases gradually as the dot radius increases; (ii) ionization energy for the ground state (1s) is high compared to the excited states (1p and 1d states) and (iii) a linear trend for 1p–1d transition is obtained.

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BUCHHOLZ, S. S., S. F. FISCHER, U. KUNZE, D. SCHUH e G. ABSTREITER. "TRANSPORT PROPERTIES OF TUNNEL-COUPLED ONE-DIMENSIONAL CHANNELS FROM AN ELECTRON BILAYER SYSTEM IN PERPENDICULAR MAGNETIC FIELD". International Journal of Modern Physics B 23, n. 12n13 (20 maggio 2009): 2910–14. http://dx.doi.org/10.1142/s0217979209062530.

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In a tunnel coupled GaAs / AlGaAs electron bilayer system (BLS), we compare transport measurements of 1D quantum Hall (QH) edge channels with lithographically defined quantum point contacts (QPCs). The electron densities in both systems can be varied by a top-gate. In a perpendicular magnetic field, Landau level mixing is observed in the QH regime, and indications of crossings of spin split QPC subbands are detected.

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Kiener, C., L. Rota, K. Turner, J. M. Freyland, A. C. Maciel, J. F. Ryan, U. Marti, D. Martin, F. Morier-Gemoud e F. K. Reinhart. "3D-to-1D carrier scattering in GaAs V-groove quantum wires". Solid-State Electronics 40, n. 1-8 (gennaio 1996): 257–60. http://dx.doi.org/10.1016/0038-1101(95)00260-x.

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ZHANG, LI. "SURFACE POLARON SELF-ENERGY AND EFFECTIVE MASS IN A WURTZITE GaN NANOWIRE". International Journal of Modern Physics B 23, n. 16 (30 giugno 2009): 3403–16. http://dx.doi.org/10.1142/s0217979209052741.

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The ground-state self-trapping energy and effective mass of surface polarons in a freestanding wurtzite GaN nanowire (NW) are studied using the second-order perturbation approach. Based on the dielectric continuum and Loudon's uniaxial crystal models, the polar optical phonon modes in the one-dimensional (1D) systems are analyzed, and the vibrating spectra of surface optical (SO) modes and electron–SO phonon coupling functions are discussed and analyzed. The calculations of the ground-state polaron self-trapping energy and the correction of effective mass due to the SO phonon modes in the 1D GaN NWs reveal that the polaron self-trapping energy and the correction of effective mass is far larger than those in 1D GaAs NW systems. The reasons for this obvious difference in the two 1D structures can be attributed to the different electron–phonon coupling constants and electron effective masses of bulk material constituting the two types of 1D confined systems. Finally, the polaronic properties of the wurtzite 1D GaN NWs are compared with those of wurtzite GaN -based two-dimensional quantum wells. The physical origins leading to these characteristics and their distinction in the different-dimensionality systems is carefully analyzed.

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Roshan, R., N. I. Cade, A. C. Maciel, J. F. Ryan, A. Schwarz, Th Schäpers e H. Lüth. "2D–1D crossover from quantum well to quantum wire behaviour in GaAs v-groove structures". Physica E: Low-dimensional Systems and Nanostructures 13, n. 2-4 (marzo 2002): 174–77. http://dx.doi.org/10.1016/s1386-9477(01)00513-6.

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Xosrovashvili, Georgi, e Nima E. Gorji. "Numerical Simulation of Carbon Nanotubes/GaAs Hybrid PV Devices with AMPS-1D". International Journal of Photoenergy 2014 (2014): 1–6. http://dx.doi.org/10.1155/2014/784857.

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The performance and characteristics of a hybrid heterojunction single-walled carbon nanotube and GaAs solar cell are modelled and numerically simulated using AMPS-1D device simulation tool. The device physics and performance with different junction parameters are analysed. The results suggest that the open-circuit voltage changes very slightly by changing the electron affinity, acceptor and donor density while the other electrical parameters reach an optimum value. Increasing the concentration of a discrete defect density in the absorber layer decreases the electrical parameters. The current-voltage characteristics, quantum efficiency, band gap, and thickness variation of the photovoltaic response will be quantitatively considered.

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Jao, Ruei Fu, De Yu Luo e Jin Zhi Lai. "Tunable Quasistationary States in a One-dimensional Quantum Heterostructure". Journal of Physics: Conference Series 2449, n. 1 (1 marzo 2023): 012039. http://dx.doi.org/10.1088/1742-6596/2449/1/012039.

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Abstract In this work, we focus on the quasistationary states, lifetime, and transmittance in opened quantum wells with biased and unbiased. In order to solve the quasibound states, the complex eigenenergies are solved in our calculation model by adaptive finite element method. We have demonstrated the accuracy to exam the numerical convergence. In this case, the 1D quantum heterostructure is commonly composed of GaAs and AlxGa1-xAs. With the different applied bias, the resonant tunneling and transmittance profiles could be changed, respectively. Increasing the thickness of the outermost barrier can be prevented an electron penetrated through the barrier from the quasistationary state. This is a useful way to design easily the high-speed switch for semiconductor devices. Our results of numerical calculations are good agreement with the argument principle method approach. These results are useful and helped us to design quantum devices and quantum computations.

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Christen, J., E. Kapon, M. Grundmann, D. M. Hwang, M. Joschko e D. Bimberg. "1D Charge Carrier Dynamics in GaAs Quantum Wires Carrier Capture, Relaxation, and Recombination". physica status solidi (b) 173, n. 1 (1 settembre 1992): 307–21. http://dx.doi.org/10.1002/pssb.2221730130.

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LI, YIMING. "NUMERICAL CALCULATION OF ELECTRON ENERGY STATES FOR NANOSCOPIC InAs/GaAs QUANTUM RINGS". International Journal of Modern Physics C 14, n. 08 (ottobre 2003): 995–1005. http://dx.doi.org/10.1142/s0129183103005789.

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In this paper we study the electron energy states for nanoscopic semiconductor quantum rings. The effective one-band Hamiltonian approximation and the Ben Daniel–Duke boundary conditions are simultaneously considered in our three-dimensional (3D) model. The rectangular and ellipsoidal torus-shaped rings have been investigated with the 3D model. The proposed model is numerically solved with nonlinear iterative method. This computational method calculates the solution without any fitting parameters and is robust for all simulation cases. For InAs/GaAs quantum rings, it is found that (1) there is a significant energy difference between the 2D and 3D models; (2) the electron energy state depends strongly on the ring shape and size; and (3) the dependency of the energy state on an external magnetic field is different from conventional 1D/2D periodical result. We find the electron energy state nonperiodically oscillates versus the applied magnetic field which is in agreement with the experimental observation.

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Reilly, D. J., L. N. Pfeiffer, G. R. Facer, K. W. West, A. S. Dzurak, B. E. Kane, R. G. Clarke, P. J. Stiles, J. L. O'Brien e N. E. Lumpkin. "Many-body Spin Interactions in Semiconductor Quantum Wires". Australian Journal of Physics 53, n. 4 (2000): 543. http://dx.doi.org/10.1071/ph00040.

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Zero length quantum wires (or point contacts) exhibit unexplained conductance structure close to 0.7 � 2e 2 /h in the absence of an applied magnetic field. We have studied the density- and temperature-dependent conductance of ultra-low-disorder GaAs/AlGaAs quantum wires with nominal lengths l=0 and 2�m, fabricated from structures free of the disorder associated with modulation doping. In a direct comparision we observe structure near 0.7 � 2e 2 /h for l = 0, whereas thel = 2�m wires show structure evolving with increasing electron density to 0.5 � 2e 2 /h in zero magnetic field, the value expected for an ideal spin-split sub-band. Our results suggest the dominant mechanism through which electrons interact can be strongly affected by the length of the 1D region.

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Shankar Sahoo, Girija, e Guru Prasad Mishra. "Design and modelling of InGaP/GaSb tandem cell with embedded 1D GaAs quantum superlattice". IET Circuits, Devices & Systems 14, n. 4 (19 marzo 2020): 471–76. http://dx.doi.org/10.1049/iet-cds.2019.0299.

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Shiri, J., J. Khalilzadeh e SH Asadpour. "Optical properties of ⁸⁷Rb atomic vapor near the 1D photonic crystal bandgap and all-optical switching of transmitted light". Physica Scripta 97, n. 3 (10 febbraio 2022): 035503. http://dx.doi.org/10.1088/1402-4896/ac50c6.

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Abstract We investigate the steady-state and dynamic behavior of the optical properties of the laser pulse in a GaAs/AlAs 1D photonic crystal (1DPC) with an atomic vapor defect layer. We chose the atomic vapor of the 87Rb as a defect layer by driving the probe field on the D2 transition between 52P3/2 - 52S1/2 levels through the 1DPC. The effect of the photonic bandgap (PBG) on the absorption and dispersion properties of the probe field is discussed. Moreover, the transmission and reflection coefficient of the 1DPC is controlled by applying the various value of the intensity of the coupling field. By comparing these results in the vacuum and near the PBG, we find that the absorption/dispersion and transmission/reflection properties are strongly affected by the PBG. We find that all-optical properties of atomic vapor in the surrounding of 1DPC are improved due to PBG. Furthermore, the effect of the intensity of the coupling field on the all-optical switching is studded. The proposed model may provide some new possibilities for technological applications as an all-optical device based on the photonic crystal in quantum information science, quantum computing, signal processing, and quantum communications.

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Семенов, M. Б., В. Д. Кревчик, Д. O. Филатов, A. В. Шорохов, A. П. Шкуринов, И. А. Ожередов, П. В. Кревчик et al. "Диссипативное туннелирование электронов в вертикально связанных двойных асимметричных квантовых точках InAs/GaAs(001)". Журнал технической физики 91, n. 10 (2021): 1431. http://dx.doi.org/10.21883/jtf.2021.10.51354.66-21.

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We report on the results of experimental studies of the photoelectric properties of a GaAs p-i-n photodiode with InAs/GaAs(001) double asymmetric quantum dots (DAQDs) grown by self-assembling in Metal Organic Vapor Phase Epitaxy (MOVPE) process. Three peaks were observed in the dependence of the photocurrent on the reverse bias measured at monochromatic photoexcitation of the DAQDs at the wavelength corresponding to the energy of interband optical transitions between the ground hole and electron states in the bigger QDs. These peaks were related to the tunneling of the photoexcited electrons between the QDs including the dissipative one (with emission and absorption of the optical phonons). The experimental results agree qualitatively with the theoretical field dependence of the 1D dissipative tunneling probability between the QDs.

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Kohl, M., D. Heitmann, P. Grambow e K. Ploog. "Effect of the wire width on 1D magneto excitons in GaAs-AlGaAs quantum-well wires". Surface Science 229, n. 1-3 (aprile 1990): 248–51. http://dx.doi.org/10.1016/0039-6028(90)90881-8.

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Gu, Lehua, Shuang Wu, Shuai Zhang e Shiwei Wu. "Nanoscale Impact Ionization and Electroluminescence in a Biased Scanning-Tunneling-Microscope Junction". Chinese Physics Letters 39, n. 3 (1 marzo 2022): 037801. http://dx.doi.org/10.1088/0256-307x/39/3/037801.

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Electroluminescence from a p-type GaAs(110) surface was induced by tunneling electrons in a scanning tunneling microscope under both polarities of bias voltage. The optical spectra exhibit a polarity-independent luminescence peak at 1.47 eV resulting from the exciton recombination. However, the quantum yield of photon emission at negative bias voltage is two orders of magnitude weaker than that at positive bias voltage. Moreover, the luminescence at negative bias voltage shows the linear dependence of bias voltage, distinct from the rapid rise due to resonant electron injection at positive bias. Furthermore, the threshold bias voltage for electroluminescence at negative bias is nearly twice the bandgap of GaAs, not simply satisfying the energy conservation for the creation of an electron-hole pair. Through theoretical calculation, we propose an impact ionization model to nicely explain the newly observed electroluminescence at negative bias voltage. We believe that this mechanism of impact ionization could be readily applied to other nanoscale optoelectronics including 2D semiconductors and 1D nanostructures.

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Kovalenko, Konstantin L., Sergei I. Kozlovskiy, Nicolai N. Sharan e Eugeniy F. Venger. "Multi-ion scattering of charged carriers by ionized impurities in heavily doped semiconductors: From bulk to nanowires". Journal of Applied Physics 131, n. 12 (28 marzo 2022): 125708. http://dx.doi.org/10.1063/5.0081033.

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Analytical expressions for the low-field mobility in heavily doped 3D, 2D, and 1D semiconductor structures are obtained using the quantum-kinetic approach. The study takes into account the multi-ion ( M-ion) scattering of charge carriers by ionized impurities. The calculated dependences of the carrier mobility on doping concentration are compared with experiment in the heavily doped bulk materials (3D) Si, InP, GaAs, n-In0.49Ga0.51P, in heavily doped In0.15Ga0.85As quantum wells and InN nanowires, respectively. When calculating mobility in n-Si, the anisotropic effective masses of electrons in the valleys are taken into account. We explain the difference in the electron mobility of n-Si bulk crystals heavily doped by phosphorus and arsenic in the framework of the M-ion scattering model, which considers the scattering of electrons by interaction potentials with two characteristic lengths: the screening length and the effective radius of the doping ion. The number of ions M participating in the scattering process depends on the effective masses of charge carriers. For the light carriers with effective masses [Formula: see text] ([Formula: see text] is the free electron mass), the two-ion ( M = 2) scattering is more probable. For carriers with higher effective masses, three- and four-ion scattering is relevant.

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Volodin, V. A., e M. D. Efremov. "Photoluminescence study of type-II GaAs quantum well wires grown on nano-faced (311)A surface: Quasi-1D exciton observation?" Microelectronics Journal 37, n. 12 (dicembre 2006): 1557–60. http://dx.doi.org/10.1016/j.mejo.2006.05.022.

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