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Academic literature on the topic 'Exciton g-Factor'

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Published: 24 June 2023

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Journal articles on the topic "Exciton g-Factor"

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SCHMIDT, T., L. WORSCHECH, M. SCHEIBNER, T. SLOBODSKYY, L. W. MOLENKAMP, and A. FORCHEL. "SPIN POLARIZATION IN SEMIMAGNETIC CdMnSe/ZnSe QUANTUM DOTS WITH ZERO EXCITON g FACTOR." International Journal of Modern Physics B 21, no. 08n09 (April 10, 2007): 1626–31. http://dx.doi.org/10.1142/s0217979207043324.

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We have investigated the degree of circular polarization (ρ) in the emission of semimagnetic CdMnSe/ZnSe quantum dots (QDs) with Mn contents of nominally 0, 1 and 2 %. Circularly polarized excitation was used to control the polarization of the excited carriers. The g factors were determined from the dependence of ρ on the magnetic field strength. We demonstrate that in QDs with 1 % Mn the exciton g factor is vanishingly small. We also present measurements on the excitation power dependent changes of the polarization. A direct heating mechanism is identified as origin of the drastic enhancement of the g factor by ramping up the excitation power. For high laser powers the exciton g factor increases by a factor of 30. In addition, by comparing the luminescence polarization of QDs with 2 % Mn and without Mn a sign reversal of the g factor was observed.
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Lalitha, D., A. John Peter, and Chang Woo Lee. "Magneto-trions in a GaMnAs/Ga0.6Al0.4As Quantum Dot." International Journal of Nanoscience 14, no. 05n06 (October 2015): 1550023. http://dx.doi.org/10.1142/s0219581x15500234.

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Magneto bound exciton and the charged exciton in a GaMn 0.02 As / Ga 0.6 Al 0.4 As quantum dot are reported with the spatial confinement effect. The numerical calculations are carried out with the inclusion of exchange interaction between the carrier and the magnetic impurities. The binding energies of exciton and the trions and the optical transition energy are obtained as a function of dot radius. Numerical computations are followed using exact diagonalization method. The spin polaronic energy of the exciton and the charged excitons are obtained using a mean field theory in the presence of magnetic field strength. The magnetization of Mn ion impurities as a function of dot radius is investigated. The effective g-factor of conduction (valence) band electron (hole) is obtained in the GaMnAs quantum dot. The magnetic field induced size dependence of effective Landé g-factor is computed. The result shows that (i) the geometrical dependence on sp-d exchange interaction in the GaMn 0.02 As / Ga 0.6 Al 0.4 As quantum dot has great influence with the geometrical confinement, (ii) the monotonic behavior of effective g-factor with the reduction of dot radius is observed, (iii) the Landé factor is more sensitive if the geometrical confinement effect is included and (iv) the value of effective g-factor increases when the spatial confinement is enhanced for all the dot radii. Our results show that the effective Landé g-factor can be manipulated negative to positive values in the GaMn 0.02 As / Ga 0.4 Al 0.6 As quantum dot.
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N. R. Senthil Kumar, N. R. Senthil Kumar, A. John Peter A. John Peter, and Chang Woo Lee Chang Woo Lee. "Optical properties of excitons in strained Gax In1-xAs/GaAs quantum dot: ef fect of geometrical conf inement on exciton g-factor." Chinese Optics Letters 11, no. 8 (2013): 082501–82507. http://dx.doi.org/10.3788/col201311.082501.

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Ju, Long, Lei Wang, Ting Cao, Takashi Taniguchi, Kenji Watanabe, Steven G. Louie, Farhan Rana, et al. "Tunable excitons in bilayer graphene." Science 358, no. 6365 (November 16, 2017): 907–10. http://dx.doi.org/10.1126/science.aam9175.

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Excitons, the bound states of an electron and a hole in a solid material, play a key role in the optical properties of insulators and semiconductors. Here, we report the observation of excitons in bilayer graphene (BLG) using photocurrent spectroscopy of high-quality BLG encapsulated in hexagonal boron nitride. We observed two prominent excitonic resonances with narrow line widths that are tunable from the mid-infrared to the terahertz range. These excitons obey optical selection rules distinct from those in conventional semiconductors and feature an electron pseudospin winding number of 2. An external magnetic field induces a large splitting of the valley excitons, corresponding to a g-factor of about 20. These findings open up opportunities to explore exciton physics with pseudospin texture in electrically tunable graphene systems​.
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Faria Junior, Paulo E., Klaus Zollner, Tomasz Woźniak, Marcin Kurpas, Martin Gmitra, and Jaroslav Fabian. "First-principles insights into the spin-valley physics of strained transition metal dichalcogenides monolayers." New Journal of Physics 24, no. 8 (August 1, 2022): 083004. http://dx.doi.org/10.1088/1367-2630/ac7e21.

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Abstract Transition metal dichalcogenides (TMDCs) are ideal candidates to explore the manifestation of spin-valley physics under external stimuli. In this study, we investigate the influence of strain on the spin and orbital angular momenta, effective g-factors, and Berry curvatures of several monolayer TMDCs (Mo and W based) using a full ab initio approach. At the K-valleys, we find a surprising decrease of the conduction band spin expectation value for compressive strain, consequently increasing the dipole strength of the dark exciton by more than one order of magnitude (for ∼ 1 % – 2 % strain variation). We also predict the behavior of direct excitons g-factors under strain: tensile (compressive) strain increases (decreases) the absolute value of g-factors. Strain variations of ∼1% modify the bright (A and B) excitons g-factors by ∼0.3 (0.2) for W (Mo) based compounds and the dark exciton g-factors by ∼0.5 (0.3) for W (Mo) compounds. Our predictions could be directly visualized in magneto-optical experiments in strained samples at low temperature. Additionally, our calculations strongly suggest that strain effects are one of the possible causes of g-factor fluctuations observed experimentally. By comparing the different TMDC compounds, we reveal the role of spin–orbit coupling (SOC): the stronger the SOC, the more sensitive are the spin-valley features under applied strain. Consequently, monolayer WSe2 is a formidable candidate to explore the role of strain on the spin-valley physics. We complete our analysis by considering the side valleys, Γ and Q points, and by investigating the influence of strain in the Berry curvature. In the broader context of valley- and strain-tronics, our study provides fundamental microscopic insights into the role of strain in the spin-valley physics of TMDCs, which are relevant to interpret experimental data in monolayer TMDCs as well as TMDC-based van der Waals heterostructures.
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Burakowski, M., P. Mrowiński, M. Gawełczyk, J. P. Reithmaier, S. Höfling, and G. Sęk. "Diamagnetic coefficients and g-factors of InAs/InGaAlAs quantum dashes emitting at telecom wavelengths." Journal of Applied Physics 132, no. 14 (October 14, 2022): 144301. http://dx.doi.org/10.1063/5.0101345.

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Semiconductor nanostructures of various material systems are heavily researched for information processing applications as single-photon sources for communication and as a spin memory for storage. Here, exciton, electron, and hole properties in single InAs/InP asymmetric quantum dots (quantum dashes) emitting in a broad spectral range from 0.8 to above 1 eV are studied experimentally and theoretically. Experiments using magneto-microphotoluminescence allowed us to determine g-factor tensor components and diamagnetic coefficients. The growth-axis exciton g-factor is in a 0.0–2.9 range with a constant hole g-factor of 4.5 and variation governed by electron contribution. The in-plane g-factor is more stable with the size of the nanostructure exhibiting values of around −0.7 and −1.6 for holes and electrons, respectively. The diamagnetic coefficients are [Formula: see text] and [Formula: see text] in the growth and in-plane directions, respectively. Simulations based on the eight-band k⋅p model qualitatively reproduce the key experimental features, including the vanishing of the inverse fine-structure splitting of bright exciton at around 3 T, making these structures prospective for the generation of entangled photons.
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Turyanska, L., R. J. A. Hill, O. Makarovsky, F. Moro, A. N. Knott, O. J. Larkin, A. Patanè, et al. "Tuneable paramagnetic susceptibility and exciton g-factor in Mn-doped PbS colloidal nanocrystals." Nanoscale 6, no. 15 (2014): 8919–25. http://dx.doi.org/10.1039/c4nr02336f.

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We report on PbS colloidal nanocrystals that combine within one structure solubility in physiological solvents with near-infrared photoluminescence, and magnetic (magnetic susceptibility) and optical (exciton g-factor) properties tuneable by the controlled incorporation of magnetic impurities (Mn).
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Lacroix, Y., C. A. Tran, S. P. Watkins, and M. L. W. Thewalt. "Optical identification of the exciton–polariton in epitaxial InAs." Canadian Journal of Physics 74, S1 (December 1, 1996): 212–15. http://dx.doi.org/10.1139/p96-861.

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We report optical identification of the exciton–polariton in epitaxial InAs by combined photoluminescence, reflectance, and transmittance spectroscopy. The photoluminescence of these samples showed identifiable spectral lines a thousand times narrower than previously published results from other groups. The measurements were made at 1.4 K and at magnetic fields up to 7 T. Contrary to what is observed in other III–V semiconductors such as GaAs or InP, the free exciton (polariton) is nearly invisible in the photoluminescence spectrum without the application of a magnetic field. We believe that the relatively large residual donor concentration coupled with the large spatial extent of the exciton wave function in this material inhibit the existence of unbound excitonic recombination. Reflectance and transmittance spectroscopy provide very strong evidence that our identification is correct, and the magnetic field dependence yielded values of the electron effective mass and g-factor of (0.026 + 0.002)m0 and −15.3 ± 0.2, respectively, based on this assignment.
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Klotz, F., V. Jovanov, J. Kierig, E. C. Clark, D. Rudolph, D. Heiss, M. Bichler, G. Abstreiter, M. S. Brandt, and J. J. Finley. "Observation of an electrically tunable exciton g factor in InGaAs/GaAs quantum dots." Applied Physics Letters 96, no. 5 (February 2010): 053113. http://dx.doi.org/10.1063/1.3309684.

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Quax, G. W. W., T. E. J. Campbell Ricketts, A. M. Yakunin, T. van Lippen, R. Nötzel, P. M. Koenraad, C. A. C. Bosco, J. H. H. Rietjens, B. Koopmans, and A. Yu Silov. "All-optical control of the exciton g-factor in InAs/GaAs quantum dots." Physica E: Low-dimensional Systems and Nanostructures 40, no. 6 (April 2008): 1832–35. http://dx.doi.org/10.1016/j.physe.2007.10.089.

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Dissertations / Theses on the topic "Exciton g-Factor"

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Wang, Shuli. "Étude des propriétés électroniques des perovskites bidimensionnelles à halogénure métallique par spectroscopie magnéto-optique." Electronic Thesis or Diss., Toulouse, INSA, 2023. http://www.theses.fr/2023ISAT0004.

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Ces dernières années, les matériaux pérovskites bidimensionnels (2D) ont attiré une attention considérable en raison de leurs propriétés électroniques et optiques uniques et excellentes, qui en font un semi-conducteur extrêmement prometteur pour les applications d'émission de lumière et d'affichage. En outre, la pérovskite non magnétique peut devenir un semi-conducteur magnétique en incorporant des impuretés magnétiques dans les réseaux de la pérovskite hôte pour introduire des propriétés magnétiques. La coexistence d'excellentes propriétés optoélectroniques et magnétiques fait de la pérovskite 2D semi-magnétique un matériau très prometteur pour les dispositifs semi-conducteurs opto-spintronique pour le traitement de l'information et les communications.Dans cette thèse, nous explorons les propriétés électroniques et optiques des pérovskites 2D via la spectroscopie magnéto-optique. Nous commençons par effectuer des mesures de magnéto-photoluminescence (PL) et de magnéto-transmission sur des nanoplaquettes à base de CsPbBr3 avec une épaisseur différente de la dalle de plomb-halogénure, allant de 2 à 4 couches de plan octaédrique de plomb-halogénure. En appliquant des champs magnétiques dans le plan jusqu'à 65 T, l'état excitonique sombre optiquement inactif est éclairci. Cette approche nous permet d'observer directement une amélioration de l'émission PL du côté basse énergie du spectre PL, ce qui indique que l'état excitonique sombre optiquement inactif est l'état le plus bas dans ces nanoplaquettes. De plus, en combinant nos résultats de magnéto-PL et de magnéto-transmission avec les prédictions théoriques de la division de la structure fine de l'exciton, nous déterminons avec précision la division d'énergie entre les excitons sombres et brillants. Nous démontrons qu'en effet, la division des excitons sombres et brillants augmente avec la diminution des couches du plan octaédrique du plomb-halogénure. Nous démontrons également que l'émission efficace de ces nanoplatelles est due à un effet de goulot d'étranglement phononique, qui réduit considérablement la relaxation des excitons photoexcités vers l'état sombre optiquement inactif.Enfin, nous étudions les propriétés électroniques de la perovskite 2D (PEA)2PbI4 dopée au Mn par spectroscopie de magnéto-transmission pour différentes fractions molaires de Mn. Nous constatons que le facteur g de Lande des excitons peut être contrôlé par la concentration de Mn incorporé. Avec l'augmentation de la concentration x de Mn de 0 à 2%, le facteur g augmente, ce que nous attribuons à l'interaction d'échange sp-d entre les excitons de bord de bande et les spins hébergés dans les ions Mn. Si la concentration en Mn est encore augmentée, jusqu'à 5%, le facteur g des excitons diminue. Cette contre-tendance anormale est attribuée aux interactions Mn-Mn, qui résultent en un couplage anti-ferromagnétique efficace
Abstract: In recent years, two-dimensional (2D) perovskite materials have attracted considerable attention duo to their unique and excellent electronic and optical properties, which make them an extremely promising semiconductor for light-emitting and display applications. Furthermore, the nonmagnetic perovskite can be semi magnetic semiconductor by incorporating magnetic impurities into lattices of the host perovskite to introduce magnetic properties. The coexistence of both excellent optoelectronic and magnetic properties, makes semi magnetic 2D perovskite to be a considerably promising material for opto-spintronic semiconductor devices for information processing and communications.In this thesis, we explore the electronic and optical properties of 2D perovskites via magneto-optical spectroscopy. We start from performing magneto-photoluminescence (PL) and magneto-transmission measurements on CsPbBr3-based nanoplatelets with a different thickness of the lead-halide slab, ranging from 2 to 4 layers of lead-halide octahedral plane. By applying in-plane magnetic fields up to 65 T, the optically inactive dark excitonic state is brightened. This approach allows us to directly observe an improvement of the PL emission on the low-energy side of the PL spectrum, which indicates that the optically inactive dark excitonic state is the lowest-lying state in these nanoplatelets. Additionally, combining our magneto-PL and magneto-transmission results with theoretical predictions of the exciton fine structure splitting, we accurately determine the energy splitting between the dark and bright excitons. We demonstrate that indeed the dark-bright exciton splitting increases with decreasing layers of lead-halide octahedral plane. We also demonstrate that the efficient emission from these nanoplateltes is due to a phonon bottleneck effect, which significantly reduces the relaxation of the photo excited excitons to the optically inactive dark state.Finally, we investigate the electronic properties of Mn-doped 2D (PEA)2PbI4 perovskite via magneto-transmission spectroscopy for various Mn molar fractions. We find that the exciton Lande g-factor can be controlled by the incorporated Mn concentration. With increasing Mn concentration x from 0 to 2%, the g-factor increases, which we attribute to the sp-d exchange interaction between band-edge excitons and spins hosted in Mn ions. If the Mn concentration is increased further, up to 5%, the exciton g-factor decreases. This anomalous counter-trend is attributed to the Mn-Mn interactions, which result in an effective anti-ferromagnetic coupling
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Gonzalez, Hernandez Felix Guillermo. "Tempos de relaxação e decoerência em ensembles de pontos quânticos." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277852.

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Orientador: Gilberto Medeiros Ribeiro
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin
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Resumo: Medidas experimentais foram realizadas para determinar as escalas de tempo de relaxação e decoerência do spin eletrônico como bit quântico. A estrutura dos estados de exciton foi investigada com o objetivo de servir como estados intermediários na manipulação do spin. O sistema utilizado para o estudo de decoerência é um ensemble de pontos quânticos auto-formados semicondutores. Dois temas servem como eixos centrais dos três experimentos desenvolvidos nesta tese: a polarização de spin e o fator g de Landé. No primeiro experimento, ao incluir o efeito do reservatório térmico, foi obtido o grau de polarização do spin (populações dos níveis up e down) para as camadas s e p. O desdobramento dos níveis orbitais em subníveis de spin permitiu obter a magnitude do fator g para estes estados. Mudando a orientação do campo magnético, foram observadas as anisotropias do tensor g e a sua relação com os detalhes do potencial de confinamento. Estas características permitiram inferir o tempo de relaxação T1. A medida da polarização resolvida no tempo foi realizada através de es-pectroscopia óptica de bombeio-prova. Os pulsos de luz e o campo magnético transverso permitem que uma polarização líquida seja inicializada. A rotação de Kerr permitiu observar oscilações desta polarização em torno do campo magnético com freqüência determinada pelo fator g. A perda da coerência de fase do spin resulta no decaimento destas oscilações numa escala de tempo T2. Medidas realizadas num ensemble de spins implicam em que o tempo de decoerência encontra-se limitado pela escala de defasagem T¤2< T2. Uma técnica semelhante à refocalização por spin-eco em experimentos de ressonância magnética nuclear, foi aplicada utilizando pulsos de laser para reverter a defasagem do ensemble. Tanto a possibilidade de medir o sinal de eco como o tempo de decoerência foram medidos como função da temperatura. A estrutura de níveis de exciton e a sua distribuição no ensemble foi estudada também com espectroscopia de bombeio-prova. Foram observados batimentos quânticos entre os níveis de estrutura fina do exciton para sis-temas 0D e 2D limitados pelo tempo de recombinação
Abstract: Experimental measurements were carried out to determine the scales of the relaxation and decoherence time for the electronic spin as quantum bit. The structure of the exciton states was investigated with the objective to serve as intermediate states in the spin manipulation. The system studied for the implementation of the quantum computation is an ensemble of self-assembled semiconductor quantum dots. Two subjects serve as central axes of the three experiments developed in this thesis: the spin polarization and the Landé g-factor. In the first experiment, when including the effect of the thermal reservoir, the degree of spin polarization (populations for the up and down levels) was measured for layers s and p. The splitting of the orbital levels in spin sublevels allowed to get the magnitude of factor g for these states. Changing the orientation of the magnetic field, the g-tensor anisotropies and its relation with the details of the confinement potential had been observed. These characteristics had allowed to infer the relaxation time T1. The time resolved polarization measurement was carried out by optical pump-probe spectroscopy. The pulses of light and the transverse magnetic field allow the initialization of a net polarization. The Kerr rotation allowed to observe oscillations of this polarization around the magnetic field with frequency determined for factor g. The loss of the spin phase coherence results in the decay of these oscillations in a time scale T2. Measurements carried out in an ensemble of spins imply that the decoherence time is limited by the ensemble dephasing time T¤2 < T2. A technique similar to the spin-echo refocalization in nuclear magnetic resonance experiments using laser pulses was applied to reverse the ensemble dephasing. The possibility to measure the echo signal and the decoherence time was measured as a function of the temperature. The structure of exciton levels and its distribution in ensemble were also studied with pump-probe spectroscopy. Quantum beats were observed be-tween the fine structure exciton levels for 0D and 2D systems, yet limited by the recombination time
Doutorado
Física da Matéria Condensada
Doutor em Ciências
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Godoy, Marcio Peron Franco de. "Propriedades de pontos quânticos de InP/GaAs." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277715.

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Orientador: Fernando Iikawa
Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
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Resumo: Neste trabalho estudamos as propriedade estruturais e ópticas de pontos quânticos auto-organizados de InP crescidos sobre o substrato de GaAs. Esta estrutura apresenta o alinhamento de bandas tipo-II na interface, confinando o elétron no ponto quântico, enquanto o buraco mantém-se na barreira, próximo à interface devido à interação coulombiana atrativa. As amostras foram crescidas por epitaxia de feixe químico (CBE) no modo Stranskii-Krastanov. Os pontos quânticos apresentam raio médio de 25 nm e grande dispersão de altura (1-5 nm) e ocorre a relaxação parcial do parâmetro de rede, chegando a 2 %, em pontos quânticos superficiais. Do ponto de vista de propriedades ópticas, a fotoluminescência de pontos quânticos superficiais exibe uma eficiente emissão óptica, devido a baixa velocidade de recombinação dos estados superficiais do InP, e reflete a densidade e distribuição bimodal de tamanhos. Além disso, sua emissão óptica em função da intensidade de excitação exibe comportamento diverso em comparação com pontos quânticos cobertos com uma camada de GaAs. Em pontos quânticos cobertos, determinamos a energia de ativação térmica, que varia de 6 a 8 meV, e é associada à energia de ligação do éxciton ou energia de ionização do buraco. O decaimento temporal da luminescência de pontos quânticos é de 1,2 ns, um tempo relativamente curto para um ponto quântico tipo-II. A análise das propriedades magneto-ópticas em pontos quânticos individuais, inédita em QDs tipo-II, permitiu verificar que o fator-g do éxciton é praticamente constante, independentemente do tamanho dos QDs, devido ao fato dos buracos estarem levemente ligados. Por fim, mostramos a versatilidade do sistema acoplando-o a um poço quântico de InGaAs. Este acoplamento introduz mudanças na superposição das funções de onda do par elétron-buraco que permitem a manipulação do tempo de decaimento da luminescência e da energia de ligação excitônica
Abstract: We have investigated structural and optical properties of InP self-assembled quantum dots grown on GaAs substrate. This system presents a type-II band lineup where only electrons are confined in the InP quantum dots. The InP/GaAs quantum dots were grown by chemical beam epitaxy in the Stranskii-Krastanov mode. Our quantum dots present a mean radius of 25 nm and large height dispersion, 1-5 nm, and a partial relieve of the strain up to 2 % is observed. The photoluminescence spectra of surface quantum dots show an efficient optical emission, which is attributed to the low surface recombination velocity in InP. We observed a bimodal dispersion of the dots size distribution, giving rise to two distinct emission bands. A remarkable result is the relatively large blue shift of the emission band from uncapped samples as compared to those for capped dots. In capped quantum dots, we obtained the thermal activation energy, from 6 to 8 meV, which is associated to the exciton binding energy or hole ionization energy. The observed luminescence decay time is about 1.2 ns, relatively short decay time for type II system. We investigated magneto-optical properties using single-dot spectroscopy. The values of the exciton g factor obtained for a large number of single InP/GaAs dots are mainly constant independent of the emission energy and, therefore, of the quantum dot size. The result is attributed to the weak confinement of the holes in InP/GaAs QDs. We have also investigated structures where InP quantum dots are coupled to a InGaAs quantum well. This system permits the manipulation of the wave function overlap between electron-hole in order to control the optical emission decay time and exciton binding energy
Doutorado
Física
Doutor em Ciências
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Kucharska, A. I. "Measurement of g-factors of excited states in some medium mass nuclei using the Transient Field Technique." Thesis, University of Oxford, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375280.

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Raskin, Maxim. "Ultraschnelle Ladungsträger- und Spindynamik in II-VI und III-V Halbleitern mit weiter Bandlücke." Doctoral thesis, Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-125227.

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Die vorliegende Arbeit beschäftigt sich mit der Herstellung und Charakterisierung von verdünnten magnetischen II-VI und III-V Halbleiter-Dünnschichten. Diese Systeme bieten vereinfachte optische kohärente Kontrolle von Spin-basierten Prozessen und eignen sich hervorragend für den Einsatz in zukünftigen opto-magnetischen Anwendungen. ZnO-, ZnXO-, GaN- und GaXN-Proben (X = Mangan, Cobalt) sind mit Hilfe der naßchemischen Sol-Gel Synthese hergestellt worden. Sie werden mit Hilfe der Photolumineszenzspektroskopie untersucht. Die spektrale Position der elektronischen Niveaus in der Nähe der Bandkante dieser Materialien wird bestimmt, um in weiteren Experimenten die freien und gebundenen Exzitonen einzeln abzufragen. Mit der Methode der zeitaufgelösten differentiellen Transmissionsspektroskopie (TRDT) werden die Lebensdauern dieser Ladungsträger bestimmt und mit ultraschnellen Prozessen der optischen Anregung und Relaxation in Verbindung gebracht. Die Methode der zeitaufgelösten Faraday-Rotation-Spektroskopie (TRFR) wird angewandt, um die kohärente Spindynamik des optisch angeregten Teilchenensembles zu beschreiben. Die Kohärenz unterliegt den Störeinflüssen verschiedener Streumechanismen, die in der vorliegenden Arbeit identifiziert und quantitativ beschrieben werden. Bei einigen untersuchten Materialsystemen (ZnCoO, ZnMnO und GaMnN) wird die jeweilige spezifische Elektron-Ion Austauschenergie N0α bestimmt, welche die Kopplungsstärke der elektronischen Spins zu denen der Dotierionen beschreibt.
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SAGE, FRANCOISE. "Pompage optique du niveau metastable **(3)p : :(o) de la premiere configuration excitee des isotopes impairs des gaz rares." Caen, 1985. http://www.theses.fr/1985CAEN2039.

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Etude experimentale de ce pompage optique sur les isotopes **(21)ne, **(83)kr, **(129)xe et **(131)xe afin de mesurer le facteur de lande g(**(3)po) par des experiences de resonance magnetique en phase vapeur (**(21)ne) ou son faisceau atomique, les atomes etant portes dans l'etat metastable a l'aide d'une decharge haute frequence et pompes optiquement par un laser a colorant continu accordable, avec une precision superieure a celle des calculs a partir de la structure hyperfine
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Book chapters on the topic "Exciton g-Factor"

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Meyer, B. K. "ZnO: exciton g-factors." In New Data and Updates for IV-IV, III-V, II-VI and I-VII Compounds, their Mixed Crystals and Diluted Magnetic Semiconductors, 582. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-14148-5_323.

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Meyer, B. K. "GaN, hexagonal modification: exciton g-factors." In New Data and Updates for I-VII, III-V, III-VI and IV-VI Compounds, 251. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-48529-2_113.

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Windle, Michael. "Introduction and Overview of Statistical Approaches to Gene × Environment Interactions for Complex Phenotypes." In Statistical Approaches to Gene X Environment Interactions for Complex Phenotypes. The MIT Press, 2016. http://dx.doi.org/10.7551/mitpress/9780262034685.003.0001.

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This chapter provides an introduction and overview of important issues that served as motivations for this book. For many complex phenotypes (e.g., depression, diabetes, obesity, substance use), there is substantial evidence that while genetic influences are important, so are environmental influences; moreover, there is substantial evidence from both behavior genetic studies (e.g., twin and adoptee studies) and molecular genetic studies (both human and infrahuman) that genes commonly interact with environmental factors in predicting complex phenotypes. The fields of genomics and other –omics (e.g., proteomics, metabolomics) provide exciting opportunities to advance science and foster the goals of public health and a more individualized intervention approach (e.g., precision medicine). The goals of these more individualized approaches would benefit greatly not only by advances in genomics and other –omics, but also by incorporating information both on environments and their interactions with genomic and other biological material and regulatory processes (e.g., environmental signal to biological pathway responses). Such findings would thereby offer more flexible guidance to a broader range of prevention, intervention, and treatment targets, and facilitate more tailored programs based on a fuller complement of G and E influences.
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Calvert, Jack G., John J. Orlando, William R. Stockwell, and Timothy J. Wallington. "Mechanisms of Ozone Reactions in the Troposphere." In The Mechanisms of Reactions Influencing Atmospheric Ozone. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780190233020.003.0005.

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In Chapter I, we identified the origin of stratospheric ozone and its role in limiting the short wavelengths of sunlight reaching the Earth. We also saw the importance of trace impurities of NOx and hydrocarbons in the development of tropospheric ozone. In this chapter, we review and evaluate the chemical reactions of ozone that create the important hydroxyl (HO) radical. It is the photodecomposition of tropospheric ozone that is the major source of the important HO radical, and it is the HO radical that initiates the destruction of most of the reactive trace gases that are emitted into the atmosphere. Ozone also serves as a major reactant for removal of the alkenes and other reactive unsaturated compounds, and, in this chapter, we review and evaluate the rate coefficients and mechanisms of these reactions and the expected products that result from them. The reactions that generate oxygen atoms in their first excited electronic state, O(1D) atoms, and ultimately HO radicals within the atmosphere are initiated through ozone photodecomposition: . . . O3 (X1A1) + hν → O(1D) + O2(a1Δg) (I) . . . . . . → O(1D) + O2(X3Σ–g) (II) . . . A fraction of the O(1D) atoms formed in the reactions (I) and (II) react with water molecules to generate HO radicals in reaction (1) and a larger fraction are deactivated by collisions with N2 and O2 molecules to form ground state O(3P) atoms in reaction (2): . . . O(1D) + H2O → HO + HO (1) . . . . . . O(1D) + M (N2, O2) → O(3P) + M (N2, O2) (2) . . . The competition between H2O and other air molecules (N2, O2) for reaction with O(1D) atoms results in HO generation being dependent on relative humidity. Rate coefficients for reaction of O(1D) with H2O, N2, and O2 at 298 K (in units of 10−10 cm3 molecule−1 s−1) recommended by the International Union of Pure and Applied Chemistry (IUPAC) panel are 2.14, 0.31, and 0.40, respectively (Atkinson et al., 2004). To better understand the factors that control HO formation, we will review ozone photochemistry, its cross sections, quantum yields of its major photodecomposition modes, and its photolysis frequencies under varied atmospheric conditions.
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Conference papers on the topic "Exciton g-Factor"

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Senthilkumar, N. R., and A. John Peter. "Effects of gallium alloy content and the geometrical confinement on effective exciton g-factor in a III-V semiconductor quantum dot." In SOLID STATE PHYSICS: PROCEEDINGS OF THE 57TH DAE SOLID STATE PHYSICS SYMPOSIUM 2012. AIP, 2013. http://dx.doi.org/10.1063/1.4791389.

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Stuchbery, Andrew E. "Excited-state g-factor measurements with radioactive ion beams." In MAPPING THE TRIANGLE: International Conference on Nuclear Structure. AIP, 2002. http://dx.doi.org/10.1063/1.1517982.

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STONE, N. J. "METHODS FOR G-FACTOR MEASUREMENTS ON SHORT-LIVED EXCITED STATES USING RADIOACTIVE BEAMS." In Proceedings of the International Symposium. WORLD SCIENTIFIC, 2004. http://dx.doi.org/10.1142/9789812702401_0044.

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Taylor, M. J. "g Factor Measurement of the Excited 2+ State in the fp Shell Nucleus 44Ca." In MAPPING THE TRIANGLE: International Conference on Nuclear Structure. AIP, 2002. http://dx.doi.org/10.1063/1.1517984.

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Guevara, Z. E., and D. A. Torres. "Lifetime and g-factor measurements of excited states using Coulomb excitation and alpha transfer reactions." In THERMOPHYSICS 2016: 21st International Meeting. Author(s), 2016. http://dx.doi.org/10.1063/1.4955347.

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Guan, Huapeng, Robert W. Hellwarth, Jouni P. Partanen, and Nansheng Tang. "The optical polarizability of excited C60 molecules." In Nonlinear Optics: Materials, Fundamentals and Applications. Washington, D.C.: Optica Publishing Group, 1996. http://dx.doi.org/10.1364/nlo.1996.nthe.10.

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Over a dozen reports of optically-induced changes of up to a factor of 5 in the absorption cross-section of the C60 molecule at 532 nm1 have prompted us to investigate whether there might be a correspondingly large change in the (in-phase) polarizability of C60 at the same wavelength. Unfortunately for nonlinear optical applications, we have found a negative answer: the change is less than 3% for the polarizability of C60 upon excitation to either the lowest singlet or triplet state. In the course of this investigation, we have made, we believe, a more accurate determination of the absorption cross-sections σS and σT of the lowest excited singlet and triplet states of C60 molecules. This is achieved with a picosecond pump-probe technique not previously applied to C60. Our measurements of the polarizability changes were done with time-delayed degenerate four-wave mixing experiments. Our experiments were performed in a solution of 0.68 g/L of C60 in benzene.
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Bochove, E. J., and P. W. Milonni. "Radiative Momentum Transfer to Atoms by a Phase-Conjugate Mirror." In OSA Annual Meeting. Washington, D.C.: Optica Publishing Group, 1989. http://dx.doi.org/10.1364/oam.1989.pd8.

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We demonstrate, by solution of the Heisenberg equations of motion of the pseudo-spin and momentum operators of a two-level atom interacting with a phase- conjugate mirror (PCM) and a quantized radiation field, that a force is exerted by the PCM on the ground state atom. The expression found for the force is F=gRA(P1-P2)pvn̂, where P1 and P2 are the ground and excited state occupation probabilities, A=Einstein A-coefficient, pv=photon momentum at resonance, R=PCM reflectivity, n̂=unit outward normal to the PCM, and g=an aperture factor (g=9/64 for a dipole parallel to the plane of the PCM and solid angle=Ω= 2╔) . This result has a simple physical interpretation in terms of vacuum fields that are conjugated or amplified by the PCM (1,2).
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Wang, Qi, Da Xing, Wei Liu, Yongkang Cheng, and Zuguang Ma. "Study of stimulated emission from high-lying F ′ Σ g + — B ′ Π 4 and new cascade radiation in Na2." In International Laser Science Conference. Washington, D.C.: Optica Publishing Group, 1986. http://dx.doi.org/10.1364/ils.1986.ff4.

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The first observation is reported of a stimulated emission at 0.75–0.81 μm for the high-lying F ′ Σ g + — B ′ Π 4 transition and a new cascade radiation at 1.14–1.18 μm for the F ′ Σ g + → 2 ′ Σ 4 + — 2 ′ Σ g + transition in sodium vapor, two-photon resonantly pumped by an excimer laser–dye laser (rhodamine 6G) tunable over a 570–615-nm range. The lasing at 0.75–0.81 μm is recorded in Na2 at 500 °C and buffer argon pressures of 0.5, 5, and 100 Torr, respectively. At higher pressures the operating temperature range at which laser action can occur is very limited. A comparison of the theoretically calculated datum-Derslands table, the Franck-Condon factors, and experimental results—two-pump photon energy and observed lasing wave-length—shows that a kinetic channel should be as follows: the sodium dimers at the ground state are pumped to the vibrational level v = 15 for the high-lying excited state F ′ Σ g + through the vibrational level v = 24 for the intermediate state F ′ Σ 4 + and then F ′ Σ g + → B ′ Π 4 stimulated emission at 0.75–0.81 μm occurred. In the same two-photon pumping conditions for the F ′ Σ g + state the second emission band was observed at 1.14–1.18 μm, which is characterized by the vapor temperature condition, originating in our opinion, from the final process of the cascade transition F ′ Σ g + — 2 ′ Σ 4 + — 2 ′ Σ g + .
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RAMAYYA, A. V., C. GOODIN, K. LI, J. K. HWANG, J. H. HAMILTON, Y. X. LUO, A. V. DANIEL, et al. "TECHNIQUE FOR MEASURING ANGULAR CORRELATIONS AND g-FACTORS OF EXCITED STATES WITH LARGE MULTI-DETECTOR ARRAYS: AN APPLICATION TO NEUTRON RICH NUCLEI PRODUCED IN SPONTANEOUS FISSION." In Proceedings of the 9th International Spring Seminar on Nuclear Physics. WORLD SCIENTIFIC, 2008. http://dx.doi.org/10.1142/9789812779038_0007.

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Saikia, Bhaskarjyoti, Girish Kulkarni, Hrushikesh Sathe, Pravin Kakde, Tanmay Vyas, and Yiran Li. "Prediction of Exhaust System Vibration Through Harmonic Analysis & High Cycle Fatigue Life Evaluation." In ASME 2021 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/icef2021-67753.

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Abstract Exhaust system typically experiences vibration during engine operating conditions due to periodic disturbing forces (firing force and inertia force) which are generated from the engine. Natural frequency of the exhaust system gets excited due to the periodic forces causing resonance which often leads to high cycle fatigue (HCF) failure. Turbocharger is a part of exhaust system and it is mounted on the exhaust manifold. The periodic forces are transferred from engine base (Cylinder head and Block) and these forces gets amplified to overhanging components like exhaust system turbocharger. It is an industrywide practice to perform modal analysis to determine the natural frequencies of the system. However, modal analysis cannot predict the intensity with which the system would vibrate. Thus, we need to make some assumptions about the system vibration ‘g’ levels. Based on accuracy of this assumption, we may end up under-designing or over-designing the system. Harmonic analysis enables us to accurately predict the ‘g’ level at turbocharger using experimental cylinder head base excitations. After recording the correlation with experimental data in many cases it was found that this approach further aided in establishing damping constant factor of the exhaust manifold at elevated temperature. This analysis process has been validated with multiple cases as it has turned out to be a potential approach while doing design risk assessments and optimizing the engine vibration validation efforts. The benefit of prediction of exhaust system vibration level allows us to avoid iterative design process in the early stage of product development thus optimizing the design by taking advantage of shifting the natural frequency of exhaust system to lower source excitation (cylinder head). This saves vast amount of simulation lead time. Another benefit of this process is that the prediction of resonance condition of exhaust system through simulation helps us to estimate the fatigue life against the predicted ‘g’ level.
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