The effect of a weak magnetic field on the variable-range hopping regime in GaAs

Abstract

Low-T magnetotransport data on epitaxial n-type GaAs, in the variable-range hopping regime, is presented at low magnetic field. The influence of the magnetic field on the parameters of Mott's law sigma = sigma 0 exp(-(T0/T)s) is examined and appears to be very significant. A minimum in the variations of the magnetoresistance as a function of the magnetic field is attributed to two opposing mechanisms and is studied semi-empirically. The weak dependence of the magnetoresistance on the angle between the current and the magnetic field appears to be a distinctive feature of these two mechanisms.