Electromagnetic waves in quantum Hall superlattices and magnetoimpurity modes

The dispersion and damping of new electromagnetic modes are obtained in a m odel superlattice with conventional and quantum Hall (QH) effects in conduc ting layers. Two separate cases are considered: the magnetoimpurity waves a rising from the admixture of the impurity states to the classical conductiv ity in conduction layers and quantum Helicon mode originating in the nondis sipative quantum Hall effect state in the plateau regions. The novelity of this mode is in taking into account the polarization currents, contributing to the imaginary part of the diagonal conductivity. It is conjectured that this mode can be used to study the finite frequency breakdown of the relat ivistic invariance of the quantum Hall medium. (C) 2000 Published by Elsevi er Science B.V. All rights reserved.