Topological magneto-optical effect from skyrmion lattice

Yoshihiro D Kato; Yoshihiro Okamura; Max Hirschberger; Yoshinori Tokura; Youtarou Takahashi

doi:10.1038/s41467-023-41203-y

Topological magneto-optical effect from skyrmion lattice

Nat Commun. 2023 Sep 5;14(1):5416. doi: 10.1038/s41467-023-41203-y.

Authors

Yoshihiro D Kato¹, Yoshihiro Okamura², Max Hirschberger^{1

3}, Yoshinori Tokura^{1

3

4}, Youtarou Takahashi^{5

6}

Affiliations

¹ Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo, 113-8656, Japan.
² Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo, 113-8656, Japan. okamura@ap.t.u-tokyo.ac.jp.
³ RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan.
⁴ Tokyo College, University of Tokyo, Tokyo, 113-8656, Japan.
⁵ Department of Applied Physics and Quantum Phase Electronics Center, University of Tokyo, Tokyo, 113-8656, Japan. youtarou-takahashi@ap.t.u-tokyo.ac.jp.
⁶ RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan. youtarou-takahashi@ap.t.u-tokyo.ac.jp.

Abstract

The magnetic skyrmion is a spin-swirling topological object characterized by its nontrivial winding number, holding potential for next-generation spintronic devices. While optical readout has become increasingly important towards the high integration and ultrafast operation of those devices, the optical response of skyrmions has remained elusive. Here, we show the magneto-optical Kerr effect (MOKE) induced by the skyrmion formation, i.e., topological MOKE, in Gd₂PdSi₃. The significantly enhanced optical rotation found in the skyrmion phase demonstrates the emergence of topological MOKE, exemplifying the light-skyrmion interaction arising from the emergent gauge field. This gauge field in momentum space causes a dramatic reconstruction of the electronic band structure, giving rise to magneto-optical activity ranging up to the sub-eV region. The present findings pave a way for photonic technology based on skyrmionics.