Photoinduced Topological Phase Transitions in Topological Magnon Insulators

TL;DR

This paper explores how light can induce and control topological phase transitions in magnon insulators, enabling manipulation of their topological properties and potential applications in spintronics.

Contribution

It introduces a magnonic Floquet-Bloch theory to demonstrate photoinduced topological phase transitions and the creation of topological magnon semimetals in kagome ferromagnets.

Findings

Varying light intensity changes topological phases and Berry curvature.

Periodically driven systems can become gapless topological magnon semimetals.

Controlled topological transitions are achievable with electromagnetic irradiation.

Abstract

Topological magnon insulators are the bosonic analogs of electronic topological insulators. They are manifested in magnetic materials with topologically nontrivial magnon bands as realized experimentally in a quasi-two-dimensional (quasi-2D) kagome ferromagnet Cu(1-3, bdc), and they also possess protected magnon edge modes. These topological magnetic materials can transport heat as well as spin currents, hence they can be useful for spintronic applications. Moreover, as magnons are charge-neutral spin-${\bf 1}$ bosonic quasiparticles with a magnetic dipole moment, topological magnon materials can also interact with electromagnetic fields through the Aharonov-Casher effect. In this report, we study photoinduced topological phase transitions in intrinsic topological magnon insulators in the kagom\'e ferromagnets. Using magnonic Floquet-Bloch theory, we show that by varying the light intensity, periodically driven intrinsic topological magnetic materials can be manipulated into different topological phases with different sign of the Berry curvatures and the thermal Hall conductivity. We further show that, under certain conditions, periodically driven gapped topological magnon insulators can also be tuned to synthetic gapless topological magnon semimetals with Dirac-Weyl magnon cones. We envision that this work will pave the way for interesting new potential practical applications in topological magnetic materials