THERMAL-CONDUCTIVITY IN THE QUANTUM HALL-EFFECT REGIME

General expressions for both components of the thermal conductivity te nsor of a two-dimensional electron gas in the presence of impurity dis order in a strong magnetic field are derived within the self-consisten t Born approximation. Analytical and numerical results are obtained fo r asymptotic and intermediate cases respectively. It is found that the shape of the thermal conductivity dependence on the chemical potentia l is governed by the relation between temperature and impurity potenti al amplitude. Both thermal conductivity components as functions of che mical potential are shown to exhibit deviations from the Wiedemann-Fra nz law for finite temperatures near Landau level positions.