Enhanced Spin Hall Response From Aligned Kramers-Weyl Points in High Chern Number Semimetals

TL;DR

This paper introduces a novel mechanism for enhancing the spin Hall effect in high Chern number semimetals by aligning Kramers-Weyl points, leading to significantly increased spin Hall conductivity and angle, supported by model and first-principles calculations.

Contribution

It identifies a new SHE enhancement mechanism based on Kramers-Weyl point alignment in high Chern number semimetals, differing from traditional spin-orbit coupling effects.

Findings

Enhanced intrinsic spin Hall conductivity and angle in certain materials.

Identification of realistic materials with superior SHE properties compared to platinum.

Validation through model Hamiltonian and first-principles calculations.

Abstract

We propose a spin Hall effect (SHE) enhancement mechanism due to Kramers-Weyl point (KWP) alignment in chiral topological semimetals with high Chern numbers (CNs). Through model Hamiltonian calculations, we identify enhancements in the intrinsic spin Hall conductivity (SHC) and the spin Hall angle (SHA). Such enhancements, attributed to a unique high CN KWP energetic alignment and a high degree of SOC-induced band nesting, strongly depend on orbital-orbital interactions. This represents a novel mechanism to enhance SHE, differing from the spin-orbit induced anticrossing mechanism in gapped systems. Guided by this principle, we corroborate our results by means of first-principles calculations and reveal multiple realistic materials with large intrinsic SHCs and even larger SHAs than Pt.