Dominance of extrinsic scattering mechanisms in the orbital Hall effect: graphene, transition metal dichalcogenides and topological antiferromagnets

TL;DR

This paper demonstrates that in doped 2D massive Dirac systems, the orbital Hall effect is predominantly driven by extrinsic scattering mechanisms, accounting for about 95% of the effect, challenging the focus on intrinsic contributions.

Contribution

It provides a comprehensive quantum kinetic analysis showing extrinsic mechanisms dominate the orbital Hall effect in realistic materials.

Findings

Extrinsic effects account for approximately 95% of the OHE in doped systems.

Fermi surface skew scattering and side jump are the main extrinsic contributions.

Intrinsic mechanisms are less significant in the presence of disorder at typical transport densities.

Abstract

The theory of the orbital Hall effect (OHE), a transverse flow of orbital angular momentum in response to an electric field, has concentrated overwhelmingly on intrinsic mechanisms. Here, using a quantum kinetic formulation, we determine the full OHE in the presence of short-range disorder using 2D massive Dirac fermions as a prototype. We find that, in doped systems, extrinsic effects associated with the Fermi surface (skew scattering and side jump) provide $\approx 95\%$ of the OHE. This suggests that, at experimentally relevant transport densities, the OHE is primarily extrinsic.