Speaker: Masataka Kawano (Technical University of Munich, host: Levente Rózsa)
Title: Gauge-field picture and thermal Hall effect of magnons in antiferromagnetic skyrmion crystals
Date: Thursday, 23 May 2024, 13.00
Place: KFKI Camps, Bldg. 1, Conference Room
Abstract:
Quasiparticle excitations in material solids often experience a fictitious gauge field, which can be a potential source of intriguing transport phenomena. In this study, we show that low-energy excitations in insulating antiferromagnetic skyrmion crystals on the triangular lattice are effectively described by magnons with an SU(3) gauge field [1,2]. The three sublattices in the antiferromagnetic skyrmion crystals introduce the three internal degrees of freedom for the magnons, which are coupled with their kinetic motion via the SU(3) gauge field originating from the combined effect of the topologically nontrivial spin texture and local antiferromagnetic couplings. We also demonstrate that the non-Abelian nature of the SU(3) gauge field breaks an effective time-reversal symmetry and contributes to a magnon thermal Hall effect. Our theory may explain the finite thermal Hall conductivity observed in a spinel compound MnSc2S4.
[1] H. Takeda et al., Nat. Commun. 15, 566 (2024).
[2] M. Kawano, arXiv:2403.11655
