Large longitudinal magnetoresistance of multivalley systems

TL;DR

This paper explains the large longitudinal magnetoresistance observed in multivalley systems like PbTe, attributing it to off-diagonal mobility tensor components, supported by theoretical and experimental agreement.

Contribution

It introduces a classical MR theory considering multivalley effects to explain large longitudinal MR, a phenomenon previously considered unlikely.

Findings

Large longitudinal MR caused by off-diagonal mobility tensor components

Theoretical results match experimental data in IV-VI semiconductors like PbTe

Linear MR at low temperatures remains unexplained by the model

Abstract

The longitudinal magnetoresistance (MR) is assumed to be hardly realized as the Lorentz force does not work on electrons when the magnetic field is parallel to the current. However, in some cases, longitudinal MR becomes large, which exceeds the transverse MR. To solve this problem, we have investigated the longitudinal MR considering multivalley contributions based on the classical MR theory. We have showed that the large longitudinal MR is caused by off-diagonal components of a mobility tensor. Our theoretical results agree with the experiments of large longitudinal MR in IV-VI semiconductors, especially in PbTe, for a wide range of temperatures, except for linear MR at low temperatures.