Hole-tunneling dynamics in biased GaAs/<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Al</mml:mi></mml:mrow><mml:mrow><mml:mn>0.35</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Ga</mml:mi></mml:mrow><mml:mrow><mml:mn>0.65</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>As asymmetri

Nido, M.; Alexander, M. Grayson; Rühle, W. W.; Köhler, K.

doi:10.1103/physrevb.43.1839

Cited by 29 publications

(11 citation statements)

References 20 publications

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“…(In principle this can also happen for holes but in this case the tunnelling rate is too small to produce measurable effects. )In previous studies of such systems [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], the widths of the coupled quantum wells differed by several monolayers leading to differences in the DX energies of 10 meV or more. In the present work however, the DQWs are only slightly asymmetric, the widths of the coupled QWs differing by only 1 or 2 monolayers (MLs).…”

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confidence: 99%

“…Two of these are due to recombination of so-called direct exciton (DX) states in which the electron and hole are in the same quantum well and two to indirect exciton (IX) states in which the electron and hole are in different wells [1][2][3][4][5][6]. A number of optical studies have been made of these systems and of the changes in line positions when the relative positions of the energy levels in the two QWs are shifted by an applied electric field F. The energies of the indirect excitons vary approximately linearly with F while those of the direct excitons are approximately fixed.…”

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Luminescence of excitons in slightly asymmetric double quantum wells

et al. 1997

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We report the first studies of exciton luminescence spectra from asymmetric double quantum wells (DQWs) of very similar width. The DQWs were of GaAs/AlGaAs and the differences in widths of the coupled wells were one or two monolayers. The coupled direct and indirect exciton states anticross with a resonance splitting of 1.33 meV. An additional luminescence line appearing at low temperatures is identified as a localized indirect exciton.An asymmetric double quantum well (DQW) in which the two QWs are separated by a narrow barrier gives rise to a minimum of four luminescence lines. Two of these are due to recombination of so-called direct exciton (DX) states in which the electron and hole are in the same quantum well and two to indirect exciton (IX) states in which the electron and hole are in different wells [1][2][3][4][5][6]. A number of optical studies have been made of these systems and of the changes in line positions when the relative positions of the energy levels in the two QWs are shifted by an applied electric field F. The energies of the indirect excitons vary approximately linearly with F while those of the direct excitons are approximately fixed. As a result, the DX and IX lines cross or rather anticross since the electrons involved in both emission processes can tunnel through the barrier separating the wells. (In principle this can also happen for holes but in this case the tunnelling rate is too small to produce measurable effects.)In previous studies of such systems [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], the widths of the coupled quantum wells differed by several monolayers leading to differences in the DX energies of 10 meV or more. In the present work however, the DQWs are only slightly asymmetric, the widths of the coupled QWs differing by only 1 or 2 monolayers (MLs). The main purpose of working with such systems is that they have the potential to operate as tunable spectrometers of non-equilibrium acoustic phonons in the important range below 1000 GHz in which phonons propagate ballistically through material such as GaAs allowing the possibility of detailed study of relaxation and other processes. This work will be discussed in a later paper. In the course of investigating these systems however we have found that the spectroscopic properties of the devices used are very well defined and, of particular note, provide the first observation of indirect exciton localization. It is that aspect of the work that is reported here.

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Luminescence of excitons in slightly asymmetric double quantum wells

et al. 1997

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“…Previous investigations of tunneling phenomena in ADQWs have shown that a resonant charge transfer in many cases actually involves an exciton tunneling from the spatially direct to indirect exciton 5, 11, 14, 74, 75. On the other hand, calculations 4, 11, 22 indicate that the tunneling between spatially direct exciton states is normally not efficient due to very weak admixture of the direct exciton wave functions.…”

Section: Discussionmentioning

confidence: 99%

“…Among the most interesting and important phenomena of carrier transfer are the resonant or nonresonant tunneling and energy relaxation 4, 5, energy level hybridization, and state entanglement 6, 7. Carriers tunneling was intensively studied in coupled quantum wells (QWs) 8–15 and in pairs of correlated quantum dots 16–19. A special interest arose to a spin dependent interwell tunneling 20.…”

Section: Introductionmentioning

confidence: 99%

Exciton states and tunneling in semimagnetic asymmetric double quantum wells

Zaı̆tsev

Brichkin

Tarakanov

et al. 2009

phys. stat. sol. (b)

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Phone: þ7 906 095 4402, Fax: þ7 496 524 97 01Exciton level structure and interwell relaxation are studied in Cd(Mn,Mg)Te-based asymmetric double quantum wells (ADQWs) by a steady-state optical spectroscopy in magnetic fields up to B ¼ 10 T. The as grown heterostructures with CdTe QWs and nonmagnetic interwell CdMgTe barrier were subjected to a rapid temperature annealing to introduce Mn and Mg atoms from opposite barriers inside the QWs which results in a formation of the ADQW with completely different magnetic field behavior of the intrawell excitons. The giant Zeeman effect in the QW with magnetic Mn ions gives rise to a crossing of the ground exciton levels in two QWs at B C $ 3-6 T which is accompanied by a reverse of the interwell tunneling direction. In a single-particle picture the exciton tunneling is forbidden at B < 1 T as supported by calculations. Experimentally, nevertheless, a very efficient interwell relaxation of excitons is found at resonant excitation in the whole magnetic field range, regardless of the tunneling direction, emphasizing importance of excitonic correlations in the interwell tunneling. At nonresonant excitation an unexpectedly slow relaxation of the s À -polarized excitons from the nonmagnetic QW to the s þ -polarized ground state in the semimagnetic QW is observed at B > B C , giving rise to a nonequilibrium distribution of excitons in ADQW. A strong dependence of the total circular polarization degree on the hh-lh splitting D hh-lh in the nonmagnetic QW is found and attributed to the spin dependent interwell tunneling controlled by an exciton spin relaxation. Different charge-transfer mechanisms are analyzed in details and an elastic scattering due to a strong disorder is suggested as the main tunneling mechanism with the underlying influence of the valence band-mixing.

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“…There have been some serious controversies among different research teams regarding light (lh) and heavy hole (hh) resonant tunneling [36] [37]. A strong dependency of hole quantum transport physics upon the wave vector transversal to the main direction of transmission has been observed in the calculation of transport magnitudes (tunneling, transmission, diffusion, and so on).…”

Section: Basic Background On Potential Profile Changes With Band-mixingmentioning

confidence: 99%

Panorama fenomenológico de la evolución del perfil potencial de componentes binarios del grupo III-V

Álvarez

Anaya

Flores-Godoy

et al. 2014

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En este artículo se analiza el cambio del perfil potencial dispersor en algunos compuestos, considerando el efecto de mezcla de huecos ligeros y pesados. Esto se obtiene aplicando el Teorema de Shur´s Generalizado al problema cuadrático de autovalores obtenido a partir del problema que surge de un sistema de ecuaciones diferenciales N-acoplado del segundo orden, en el marco de la Aproximación de Masa Efectiva Multibanda. Consideramos energías incidentes menores, iguales y mayores que la altura de la barrera del potencial dispersor para diferentes compuesto binarios semiconductores del grupo III-V. En la descripción del perfil del potencial, empleamos el modelo de bandas de Kohn-lutinger (4x4) y (2x2) por completitud. Las propiedades estándar como pozo cuántico o barrera potencial de los compuestos binarios considerados, resultaron en lo general garantizadas, mas no todos los materiales seleccionados mostraron la evolución esperada en su perfil potencial: algunos que constituyen pozos cuánticos (QW) en aplicaciones tecnológicas, presentaron un comportamiento de barrera potencial efectiva (B) para huecos ligeros (lh), a diferentes rangos de energía incidente E y diferentes mezclas. En este estudio, ninguno de los compuestos con comportamiento de barrera en aplicaciones tecnológicas, evolucionó a un comportamiento de QW efectivo, válido tanto para lh como hh. Sorprendentemente todos los compuestos en este estudio que constituyen barreras en aplicaciones tecnológicas, presentaron transiciones desde QW a B para lh en el rango donde el valor de la energía es mayor que la altura de la barrera Vo.

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Hole-tunneling dynamics in biased GaAs/Al0.35Ga0.65As asymmetri

Cited by 29 publications

References 20 publications

Luminescence of excitons in slightly asymmetric double quantum wells

Luminescence of excitons in slightly asymmetric double quantum wells

Exciton states and tunneling in semimagnetic asymmetric double quantum wells

Panorama fenomenológico de la evolución del perfil potencial de componentes binarios del grupo III-V

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