Anomalous Hall effect in rhombohedral graphene

TL;DR

This paper calculates the anomalous Hall conductivity in rhombohedral graphene with various impurities, revealing how disorder influences the Hall effect in this material.

Contribution

It provides a comprehensive diagrammatic analysis of impurity effects on the anomalous Hall conductivity in rhombohedral graphene, including both Gaussian and non-Gaussian disorder.

Findings

Analytical solutions for weak dense impurities show all non-crossing diagrams contribute.

Inclusion of intersecting impurity diagrams captures diffractive skew-scattering effects.

Perturbative warping effects are significant in low-energy band structure calculations.

Abstract

Motivated by recent experiments on rhombohedral stacked multilayer graphene and the observation of the anomalous Hall effect in a spontaneous spin-valley polarized quarter metal state, we calculate the anomalous Hall conductivity for this system in the presence of two types of impurities: weak and dense as well as sparse and strong. Our calculation of $\sigma_{xy}$ is based on the Kubo-Streda diagrammatic approach. In a model with Gaussian disorder applicable to weak dense impurities, this involves all non-crossing diagrams (intrinsic, side-jump and Gaussian skew-scattering contributions) and additionally diagrams with two intersecting impurities, X and $\Psi$, representing diffractive skew-scattering processes. A "Mercedes star" diagram (non-Gaussian skew scattering) is furthermore included to treat in the case of strong, sparse impurities. We supplement our asymptotically exact analytical solutions for an isotropic model without warping effects by semi-numerical calculations accounting perturbatively for warping, which plays a crucial role in the low-energy band structure.