Interedge relaxation in a magnetic field.

Abstract

We calculate the scattering length for transitions between edge states in a two-dimensional electron gas due to short- and long-range impurities and acoustic phonons (deformation and piezoelectric interaction), assuming that the shape of the confining potential is arbitrary. The phonon scattering is found to be strongly suppressed at low temperatures, since only phonons with frequencies above some threshold can cause transitions. We consider a mechanism for impurity-assisted phonon scattering. This mechanism does not exhibit threshold behavior and, hence, is not strongly suppressed at low temperatures. Comparison to the experiment shows that the observed temperature dependence of the interedge relaxation rate is caused mainly by the thermal averaging of the long-range impurity rate while short-range impurity and phonon scattering play a minor role.