224 research outputs found
A new method for computing asymptotics of diagonal coefficients of multivariate generating functions
Let \sum_{n\in N^d} f_{n_1, ..., n_d} x_1^{n_1}... x_d^{n_d} be a
multivariate generating function that converges in a neighborhood of the origin
of C^d. We present a new, multivariate method for computing the asymptotics of
the diagonal coefficients f_{a_1n,...,a_dn} and show its superiority over the
standard, univariate diagonal method.Comment: 9 pages, no figure
Microwave-induced magnetoresistance of two-dimensional electrons interacting with acoustic phonons
The influence of electron-phonon interaction on magnetotransport in
two-dimensional electron systems under microwave irradiation is studied
theoretically. Apart from the phonon-induced resistance oscillations which
exist in the absence of microwaves, the magnetoresistance of irradiated samples
contains oscillating contributions due to electron scattering on both
impurities and acoustic phonons. The contributions due to electron-phonon
scattering are described as a result of the interference of phonon-induced and
microwave-induced resistance oscillations. In addition, microwave heating of
electrons leads to a special kind of phonon-induced oscillations. The relative
strength of different contributions and their dependence on parameters are
discussed. The interplay of numerous oscillating contributions suggests a
peculiar magnetoresistance picture in high-mobility layers at the temperatures
when electron-phonon scattering becomes important.Comment: 12 pages, 2 figure
Longitudinal conductivity and transverse charge redistribution in coupled quantum wells subject to in-plane magnetic fields
In double quantum wells electrons experience a Lorentz force oriented
perpendicular to the structure plane when an electric current is driven
perpendicular to the direction of an in-plane magnetic field. Consequently, the
excess charge is accumulated in one of the wells. The polarization of a bilayer
electron system and the corresponding Hall voltage are shown to contribute
substantially to the in-plane conductivity.Comment: 3 pages, 2 figure
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