Non-saturating magnetoresistance in heavily disordered semiconductors

Abstract

The resistance of a homogeneous semiconductor increases quadratically with magnetic field at low fields and, except in very special cases, saturates at fields much larger than the inverse of the carrier mobility, a number typically of order 1 Tesla. Here, we argue that a macroscopically disordered and strongly inhomogeneous semiconductor will instead show a non-saturating magnetoresistance, with typically a quasi-linear behaviour up to very large fields, and possibly also extending down to very low fields, depending on the degree of inhomogeneity. We offer this as a possible explanation of the observed anomalously large magnetoresistance in doped silver chalcogenides. Furthermore, our model of an inhomogeneous semiconductor can be developed into magnetoresistive devices that possess a large, controllable, linear response.