10:30 a.m., Friday, December 12, 2003
Room 2202, Physics Building

Theory of the Oscillatory Photoconductivity of 2D Electron Gas

Maxim Vavilov

(Massachusetts Institute of Technology)

Abstract: One of the most exciting recent experimental discoveries
in condensed matter physics has been the observation of the oscillatory
magnetoresistance and the zero resistance of a 2D electron gas subject to
microwave radiation. For microscopic understanding of this phenomenon we derive
the quantum Boltzmann equation for the two-dimensional electron gas at large
values of the filling factor. This equation describes all of the effects of the
electric fields on the impurity collision integral, including Shubnikov-de Haas
oscillations, smooth part of the magnetoresistance, and non-linear transport. We
use this equation to analytically analyze the effect of the external microwave
radiation on the electron transport. Particularly, we show that the dominant
contribution to the observed oscillatory magnetoresistance originates from the
non-equilibrium component of the electron distribution function rather than from
the corrections to the matrix elements of electron scattering off disorder due
to the microwave field.