Shun Okumura (University of Tokyo): Light-induced Floquet-Weyl states in three-dimensional topological matters

Abstract

A Weyl state is one of the three-dimensional (3D) topological electronic structures with a linear energy dispersion and chirality. This Weyl quasiparticle, regarded as a magnetic monopole in momentum space, leads to anomalous transport. In the aspect of material design, it is a great challenge to create and control the Weyl state through the light-matter coupling.
We have investigated the Floquet engineering of the 3D Dirac semimetals irradiated by circularly polarized light (CPL). We found two distinct mechanisms for the CPL-induced Dirac-Weyl transitions: 1. chiral gauge field and 2. 1-photon resonance [1]. We also examined the CPL-induced anomalous Hall conductivity for both mechanisms 1 and 2, and compared them with experimental results in the 3D Dirac semimetals Co₃Sn₂S₂ [2] and Bi [3], respectively.

[1] Y. Hirai, S. Okumura, N. Yoshikawa, T. Oka, and R. Shimano, Phys. Rev. Research 6, L012027 (2024).
[2] N. Yoshikawa, S. Okumura, Y. Hirai, K. Ogawa, K. Fujiwara, J. Ikeda, A. Ozawa, T. Koretsune, R. Arita, A. Mitra, A. Tsukazaki, T. Oka, and R. Shimano, Phys. Rev. B 111, 245104 (2025).
[3] Y. Hirai, N. Yoshikawa, M. Kawaguchi, M. Hayashi, S. Okumura, T. Oka, and R. Shimano, arXiv:2301.06072.