Driving spin chirality by electron dynamics in laser-excited antiferromagnets

TL;DR

This paper reveals a novel laser-induced mechanism for creating stable chiral spin textures in collinear antiferromagnets, without external fields or spin-orbit coupling, with potential applications in ultrafast spintronics.

Contribution

It introduces a new physical mechanism for imprinting spin chirality in antiferromagnets through laser-driven electron and magnetic dynamics, independent of traditional spin-orbit effects.

Findings

Laser pulses can generate quasi-stable chiral states in collinear magnets.

Chirality persists for nanoseconds despite thermal fluctuations.

The mechanism operates without external fields or intrinsic spin-orbit interaction.

Abstract

Optical generation of complex spin textures is one of the most exciting challenges of modern spintronics. Here, we uncover a distinct physical mechanism for imprinting spin chirality into collinear magnets with short laser pulses. By simultaneously treating the laser-ignited evolution of electronic structure and magnetic order, we show that their intertwined dynamics can result in an emergence of quasi-stable chiral states. We find that laser-driven chirality does not require any auxiliary external fields or intrinsic spin-orbit interaction to exist, and it can survive on the time scale of nanoseconds even in the presence of thermal fluctuations, which makes the uncovered mechanism relevant for understanding various optical experiments on magnetic materials. Our findings open a new perspective at the interaction of complex chiral magnetism with light.