OSCILLATIONS OF THE RELAXATION TIME IN STRONG MAGNETIC FIELDS

Abstract

Quantum oscillations of the longitudinal magnetoconductivity and magnetothermopower were calculated for a simple model of solid with parabolic electron band. It is shown that the main con- tribution originates in oscillations of the relaxation time. INTRODUCTION.- A strong magnetic field applied to the system of electrons causes the quantization of the electron energy spectrum. The quantum effects be- come particularly important at low temperatures and manifest themselves e.g. in the oscillatory behaviour of the magnetic susceptibility and transport coeffi- cients as functions of the magnetic field H. The theory predicts that both the density of electron states p(EF) and the electron mean lifetime =(EF) at the Fermi energy EF will oscillate while changing magnetic field /1,2/. The density of states give the main contribution to the oscillations of susceptibi- lity. In this communication we shall demonstrate that, at least for a simple model, the oscillations of the longitudinal magnetoconductivity are mainly due to the oscillations in the relaxation time. This effect will even be more pronounced in the longitu- dinal magnetothennopower S which is related to the longitudinal conductivity all by the Mott formula written in the well known form