Linear magnetoresistance due to multiple-electron scattering by low-mobility islands in an inhomogeneous conductor

Abstract

Linear transverse magnetoresistance is commonly observed in many material systems including semimetals, narrow band-gap semiconductors, multi-layer graphene and topological insulators. It can originate in an inhomogeneous conductor from distortions in the current paths induced by macroscopic spatial fluctuations in the carrier mobility and it has been explained using a phenomenological semiclassical random resistor network model. However, the link between the linear magnetoresistance and the microscopic nature of the electron dynamics remains unknown. Here we demonstrate how the linear magnetoresistance arises from the stochastic behaviour of the electronic cycloidal trajectories around low-mobility islands in high-mobility inhomogeneous conductors and that this process is only weakly affected by the applied electric field strength. Also, we establish a quantitative link between the island morphology and the strength of linear magnetoresistance of relevance for future applications. Linear magnetoresistance is a phenomenon observed in many material systems and could be used in magnetic field sensors. This paper uncovers its microscopic origin showing how it arises from multiple scattering of electrons by low-mobility islands within an inhomogeneous high-mobility semiconductor.