排序方式: 共有32条查询结果,搜索用时 46 毫秒
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V. V. Popov T. V. Teperik O. V. Polischuk X. G. Peralta S. J. Allen N. J. M. Horing M. C. Wanke 《Physics of the Solid State》2004,46(1):153-156
The terahertz absorption spectra of plasmon modes in a grid-gated double-quantum-well field-effect transistor structure is analyzed theoretically and numerically using the scattering matrix approach and is shown to faithfully reproduce strong resonant features of recent experimental observations of terahertz photo-conductivity in such a structure. 相似文献
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Vassilios Fessatidis Norman J.M. Horing 《Physica E: Low-dimensional Systems and Nanostructures》2005,27(4):487-494
We examine the collective mode spectrum for a double quantum-wire system embedded in semi-infinite polar medium, taking account of the role of optical phonons in interaction with the double quantum-wire plasmons and bulk/surface plasmons. The collective mode frequencies are exhibited as functions of qx (wavenumber parallel to the wires) and as functions of z0 (distance of first wire from the interface). We also find that the region of drift instability of the collective modes is split into two disjoint regions of instability by the optical phonons, with a region of stability between them. 相似文献
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Norman J. Morgenstern Horing 《Solid State Communications》2006,137(6):338-342
The nonlinear polarization of an electron plasma in an incident terahertz (THz) field is examined in an iterated shielded potential approximation. It is found to exhibit resonant behavior when the incident terahertz frequency matches the plasma frequency, with concomitant resonant increase of the dielectric function. Such resonant behavior substantially reduces the effectiveness of the screened impurity scattering potentials, admitting resonant increase of conduction when the THz frequency matches the plasma frequency. 相似文献
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Summary The grand potential and energy of a noninteracting uncorrelated two-dimensional electron gas subject to Landau quantization
in a magnetic field are examined here at low temperatures. The DeHaas-Van Alphen oscillatory magnetic susceptibility for the
free 2D gas is calculated and the results presented here incorporate the effects of spin (by allowing that spin splitting
may not, in general, equal Landau level separation) in formulae that have the same analytic structure for both even and odd
numbers of filled Landau levels.
Riassunto Il gran potenziale e l'energia di un gas elettronico bidimensionale non correlato non interagente, soggetto a quantizzazione di Landau in un campo magnetico, sono esaminate qui a basse temperature. La suscettibilità magnetica oscillatoria di De Haas-Van Alphen per il gas libero 2D è calcolata e i risultati presentati qui incorporano gli effetti di spin (tenendo conto che il taglio di spin non può, in generale, eguagliare uguale separazione del livello di Landau) in formule che hanno la stessa struttura analitica per numeri sia pari che dispari dei livelli completi di Landau.
Резюме В зтой работе при низких температурах исследуется потенсиал и знергия невзаимодействующего некоррелированного двумерного злектроннного газа, подчинющегося квантованию Ландау в магнитном поле. Вычисляется осцилляторная магнитная восприимчивость де Гааза-ван Альфена для свободнго двумерного газа. Полученные результаты учитывают спиновые зффекты (допуская, что спиновое расщепление в общем случае может быть не равно интервалу между уровнями Ландау) в формулах, которые имеют ту же аналитическую структуру для четного и нечетного числа заполненных уровней Ландау.相似文献
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We examine fast particle energy loss as a probe of the properties of a density modulated 2DEG in a normal magnetic field. In the high velocity limit, the local plasmon spectrum makes two separate contributions to energy loss for both the cases in which the particle velocity is parallel and perpendicular to the planar 2DEG. The inter-Landau band plasmon makes a distinct contribution to energy loss through excitation of the hybrid 2D magnetoplasmon. The other local plasmon, associated with the spread of a Landau level into a miniband by application of the periodic potential associated with the density modulation contributes to energy loss with features corresponding to Shubnikov-de Haas oscillations jointly with an amplitude envelope exhibiting oscillations associated with the commensurability of the modulation period and the cyclotron radius at the Fermi energy. 相似文献
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We analyze inelastic cotunneling through an interacting quantum dot subject to an ambient magnetic field in the weak tunneling regime under a non-adiabatic time-dependent bias-voltage. Our results clearly exhibit photon-assisted satellites and an overall suppression of differential conductance with increasing driving amplitude, which is consistent with experiments. We also predict a zero-anomaly in differential conductance under an appropriate driving frequency. 相似文献
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We explore inelastic cotunneling through a strongly Coulomb-blockaded
quantum dot attached to two ferromagnetic leads in the weak coupling limit using a generic quantum Langevin equation approach. We first develop a Bloch-type equation microscopically to describe the
cotunneling-induced spin relaxation dynamics, and then develop explicit
analytical expressions for the local magnetization, current, and its
fluctuations. On this basis, we predict a novel zero-bias anomaly of
the differential conductance in the absence of a magnetic field for the
anti-parallel configuration, and asymmetric peak splitting in a magnetic field. Also, for the same system with large polarization, we find a negative
zero-frequency differential shot noise in the low positive bias-voltage
region. All these effects are ascribed to rapid spin-reversal due to
underlying spin-flip cotunneling. 相似文献