Valley-Dependent Magnetoresistance in Two-Dimensional Semiconductors

TL;DR

This paper theoretically predicts a valley-dependent magnetoresistance effect in 2D semiconductors with potential applications in valleytronics, arising from Berry curvature, magnetic fields, and disorder.

Contribution

It introduces a novel valley-dependent magnetoconductivity effect in 2D semiconductors, derived from quantum kinetic theory, linking Berry curvature and magnetic fields.

Findings

Valley-dependent magnetoconductivity is odd in valley index and magnetic field.

Effect can be used to detect valley polarization experimentally.

Theoretical framework based on quantum kinetic theory.

Abstract

We show theoretically that two-dimensional direct-gap semiconductors with a valley degree of freedom, including monolayer transition-metal dichalcogenides and gapped bilayer graphene, have a longitudinal magnetoconductivity contribution that is odd in valley and odd in the magnetic field applied perpendicular to the system. Using a quantum kinetic theory we show how this valley-dependent magnetoconductivity arises from the interplay between the momentum-space Berry curvature of Bloch electrons, the presence of a magnetic field, and disorder scattering. We discuss how the effect can be measured experimentally and used as a detector of valley polarization.