Charge and spin Hall conductivity in metallic graphene

TL;DR

This paper investigates how disorder and Fermi energy influence the spin Hall conductivity in metallic graphene, revealing that vertex corrections and skew scattering can significantly enhance the effect.

Contribution

It provides a detailed analysis of the disorder and Fermi energy dependence of spin Hall conductivity in metallic graphene, highlighting the potential for large observable effects.

Findings

Vertex corrections enhance intrinsic spin Hall conductivity.

Skew scattering can produce values exceeding quantized levels.

Large spin Hall conductivities are observable despite disorder.

Abstract

Graphene has an unusual low-energy band structure with four chiral bands and half-quantized and quantized Hall effects that have recently attracted theoretical and experimental attention. We study the Fermi energy and disorder dependence of its spin Hall conductivity. In the metallic regime we find that vertex corrections enhance the intrinsic spin Hall conductivity and that skew scattering can lead to its values that exceed the quantized ones expected when the chemical potential is inside the spin-orbit induced energy gap. We predict that large spin Hall conductivities will be observable in graphene even when the spin-orbit gap does not survive disorder.