Emergent chiral interaction and ultrafast optical generation of antiferromagnetic spin spirals*

Ultrafast optical manipulation of magnetic order is one of the most sought after technology for their potential application in the next generation memory devices. The theoretical understanding of underlying physics is however is still under the mist. In this presentation we present a hybrid quantum-classical approach which allows us to reveal the intertwined dynamics of electronic and magnetic degrees of freedom for several picoseconds with a resolution of femtoseconds. Using this method we successfully demonstrate how one can generate a chiral magnetic structure from a collinear antiferromagnetic chain with an ultrafast laser. Our results show that it is possible to generate such chiral structure even in absence of any spin orbit coupling. We show that the necessary chiral interactions are generated out of equilibrium with the laser. We also demonstrate that the chirality of the end configuration can be tuned with the laser parameter as well as the material parameters. We successfully show that the process is non-thermal in nature and quite robust against thermal fluctuation.