Signatures of a Liquid-Crystal Transition in Spin-Wave Excitations of Skyrmions*

Understanding the spin-wave excitations of chiral magnetic order, such as the skyrmion crystal (SkX), is of fundamental interest to confirm such exotic magnetic order. We compute the dynamical spin structure factor, extracting the spin-wave spectrum in the SkX, in the vicinity of the paramagnet to SkX transition [1]. Inside the SkX, we find six spin-wave modes, which are supplemented by another mode originating from the ferromagnetic background. Above the critical temperature Ts for the skyrmion crystallization, a diffusive regime, reminiscent of the liquid-to-crystal transition, reveals that topological spin texture of skyrmionic character starts to develop above Ts as the precursor of the SkX [2]. We discuss the opportunities for the detection of the spin waves of the SkX using inelastic-neutron-scattering experiments in manganite-iridate heterostructures [3].

References:
1. N. Mohanta, E. Dagotto and S. Okamoto, Phys. Rev. B 100, 064429 (2019)
2. N. Mohanta, A. D. Christianson, S. Okamoto, and E. Dagotto, arXiv:2005.11399 (2020)
3. N. Mohanta, S. Okamoto, and E. Dagotto, Phys. Rev. B 102, 064430 (2020)