Floquet Spin Splitting and Spin Generation in Antiferromagnets

TL;DR

This paper introduces a method to generate and control spin currents in antiferromagnets using optical fields and thermal bath engineering, bypassing the need for spin-orbit coupling.

Contribution

It proposes a novel dynamical spin splitting approach in antiferromagnets driven by optical fields, enabling spin control without relativistic effects.

Findings

Steady-state pure spin currents can be achieved in antiferromagnets.

Thermal bath engineering enables a nonrelativistic Edelstein effect.

Linear-response spin currents are generated and manipulated.

Abstract

In antiferromagnetic spintronics, accessing the spin degree of freedom is essential for generating spin currents and manipulating magnetic order, which generally requires lifting spin degeneracy. This is typically achieved through relativistic spin-orbit coupling or non-relativistic spin splitting in altermagnets. Here, we propose an alternative approach: a dynamical spin splitting induced by an optical field in antiferromagnets. By coupling the driven system to a thermal bath, we demonstrate the emergence of steady-state pure spin currents, as well as linear-response longitudinal and transverse spin currents. Crucially, thermal bath engineering enables a nonrelativistic Edelstein effect--the generation of a net spin accumulation--without relying on spin-orbit coupling. Our results provide a broadly applicable and experimentally tunable route to control spins in antiferromagnets, offering new opportunities for spin generation and manipulation in antiferromagnetic spintronics.