Chiral anomalies in 3D spin-orbit coupled metals: electrical, thermal, and gravitational anomaly

TL;DR

This paper uncovers electrical, thermal, and gravitational chiral anomalies in 3D spin-orbit coupled metals, revealing new mechanisms of chiral charge transfer and their effects on thermal spin transport, distinct from Weyl semimetals.

Contribution

It demonstrates the existence of quantum chiral anomalies involving Fermi surfaces in 3D spin-orbit coupled systems, expanding understanding beyond Weyl semimetals.

Findings

Chiral anomalies involve Fermi surface charge transfer.

Berry curvature flux influences carrier chirality.

Anomalies induce thermal spin transport like the spin Nernst effect.

Abstract

The discovery of a chiral anomaly in Weyl semimetals, the non-conservation of chiral charge and energy across two opposite chirality Weyl nodes, has sparked immense interest in understanding its impact on various physical phenomena. Here, we demonstrate the existence of electrical, thermal, and gravitational quantum chiral anomalies in 3D spin-orbit coupled systems. Notably, these anomalies involve chiral charge transfer across two Fermi surfaces linked to a single Weyl-like point, rather than across opposite chirality Weyl nodes as in Weyl semimetals. Our findings reveal that the Berry curvature flux piercing the Fermi surface plays a critical role in distinguishing the `chirality' of the carriers and the corresponding chiral charge and energy transfer. Importantly, we demonstrate that these quantum chiral anomalies lead to interesting thermal spin transport such as the spin Nernst effect. Our results suggest that 3D spin-orbit coupled metals offer a promising platform for investigating the interplay between quantum chiral anomalies and charge and spin transport in non-relativistic systems.