Laser-Irradiated CrI$_3$: When Chiral Photons Meet Topological Magnons

TL;DR

This paper explores how laser irradiation can induce and control topological magnon and spin transport in CrI$_3$, enabling ultrafast manipulation of spin currents for potential spintronic applications.

Contribution

It demonstrates the ability to switch topological phases and Hall responses in CrI$_3$ via laser fields, revealing new pathways for opto-spintronics and magnonics.

Findings

Laser fields can induce different topological phases in CrI$_3$.

Photon-dressed magnons exhibit tunable Hall responses.

Magnon spin photocurrents can be controlled by laser parameters.

Abstract

Insulating honeycomb ferromagnet CrI$_3$ has recently attracted considerable attention due to its potential use for dissipationless spintronics applications. Recently, topological spin excitations have been observed experimentally in bulk CrI$_3$ by L. Chen, et al. [Phys. Rev. X ${\bf 8}$, 041028 (2018)] using inelastic neutron scattering. This suggest that bulk CrI$_3$ has strong spin-orbit coupling and its spin Hamiltonian should include a next-nearest neighbour Dzyaloshinskii-Moriya (DM) interaction. Inspired by this experiment, we study non-equilibrium emergent photon-dressed topological spin and thermal Hall transports in laser-irradiated CrI$_3$ with and without the DM interaction. We show that the spin excitations can be manipulated into different topological phases with different Chern numbers. Most importantly, we show that the emergent photon-dressed spin and thermal Hall response can be switched to different signs. Hence, the generated magnon spin photocurrents can be manipulated by the laser field, which is of great interest in ultrafast spin current generation and could pave the way for future applications of CrI$_3$ to topological opto-spintronics and opto-magnonics.