Enhanced Spin Hall Ratio in Two-Dimensional Semiconductors

TL;DR

This paper uses advanced calculations to identify two-dimensional semiconductors with exceptionally high spin Hall ratios, introducing a new descriptor for high SHR and discovering promising materials like GaAs monolayer and Sc2CCl2.

Contribution

It presents a novel descriptor for high spin Hall ratio and applies it to a large database, identifying new 2D materials with ultrahigh SHR.

Findings

GaAs monolayer exhibits an SHR of 0.58

High-throughput screening identified Sc2CCl2 as a promising high SHR material

The proposed descriptor effectively predicts high SHR in 2D semiconductors

Abstract

The conversion efficiency from charge current to spin current via spin Hall effect is evaluated by the spin Hall ratio (SHR). Through state-of-the-art $ab~initio$ calculations involving both charge conductivity and spin Hall conductivity, we report the SHRs of the III-V monolayer family, revealing an ultrahigh ratio of 0.58 in the hole-doped GaAs monolayer. In order to find more promising 2D materials, a descriptor for high SHR is proposed and applied to a high-throughput database, which provides the fully-relativistic band structures and Wannier Hamiltonians of 216 exfoliable monolayer semiconductors and has been released to the community. Among potential candidates for high SHR, the MXene monolayer Sc$_2$CCl$_2$ is identified with the proposed descriptor and confirmed by computation, demonstrating the descriptor validity for high SHR materials discovery.