Helicity controlled spin Hall angle in the 2D Rashba altermagnets

TL;DR

This paper explores charge-to-spin conversion efficiency in 2D Rashba altermagnets, revealing a significant spin Hall angle enhancement below the band crossing point due to combined relativistic and nonrelativistic effects, with minimal skew scattering influence.

Contribution

It introduces the concept of Rashba altermagnets and demonstrates their unique spin Hall properties, contrasting with conventional ferromagnetic systems.

Findings

Enhanced spin Hall angle below the band crossing point.

Negligible skew scattering and intrinsic topological mechanisms.

Potential for manipulating spin textures in spintronic applications.

Abstract

We investigate the efficiency of charge-to-spin conversion in two-dimensional Rashba altermagnets, a class of materials that merge characteristics of both ferromagnets and antiferromagnets. Utilizing quantum linear response theory, we quantify the longitudinal and spin Hall conductivities in this system and demonstrate that a substantial enhancement of the spin Hall angle is achieved below the band crossing point through the dual effects of relativistic spin-orbit interaction and nonrelativistic altermagnetic exchange interaction. Additionally, we find that skew scattering and topology-related intrinsic mechanisms are almost negligible in this system, which contrasts with conventional ferromagnetic Rashba systems. Our findings not only advance the understanding of spin dynamics in Rashba altermagnets but also pave the way for novel strategies in manipulating charge-to-spin conversion via the sophisticated control of noncollinear in-plane and collinear out-of-plane spin textures.