Relativistic Spin-momentum locking in altermagnets

TL;DR

This paper investigates relativistic spin-momentum locking in altermagnets, revealing how spin-orbit coupling influences the symmetry and electronic properties of materials like YVO3 and MnTe, with implications for spin transport phenomena.

Contribution

It introduces the concept of relativistic spin-momentum locking in altermagnets and analyzes its manifestation in specific materials considering spin-orbit coupling effects.

Findings

Relativistic spin-momentum locking varies among spin components in altermagnets.

Symmetry breaking alters the dominant wave components of spin-momentum locking.

Canted spin components significantly affect k-space properties such as spin-Hall conductivity.

Abstract

Spin-momentum locking in altermagnets has been deeply explored in the non-relativistic limit. Including spin-orbit coupling, altermagnets exhibit antisymmetric exchange interactions, leading to spin cantings. Therefore, the spin-momentum locking differs among the three spin components Sx, Sy, and Sz, forming the relativistic spin-momentum locking. We consider orthorhombic YVO3 and hexagonal MnTe. For YVO3, the relativistic locking comprises s-, dxy -, and dxz-wave. In MnTe, the dominant component Sy of MnTe inherits the polarized charge distribution and the non-relativistic spin-momentum locking bulk g-wave, but the breaking of the C6z rotational symmetry by the Neel vector lowers the symmetry from g-wave to d-wave. The relativistic spin-momentum locking for MnTe is composed of dxz-, dyz- and s-wave. Despite small magnitudes in real space, the canted spin components contribute significant spectral weight in k-space, impacting k-space properties such as the spin-Hall conductivity.