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MA: Fachverband Magnetismus

MA 41: Spintronics (Other Effects)

MA 41.1: Vortrag

Donnerstag, 21. März 2024, 15:00–15:15, H 2013

thermal Hall effect from magnon many-body skew scattering — •Dimos Chatzichrysafis and Alexander Mook — Johannes Gutenberg-Universität Mainz, Germany

The thermal Hall effect is a developing tool to investigate charge-neutral excitations, exposing the quantum many-body ground state of correlated materials. A significant aspect regards the nature of excitations (fermions versus bosons) [1]. Although a bosonic thermal Hall effect results from a Berry curvature of quasiparticles, there is mounting evidence that this intrinsic contribution is insufficient to describe experiments [2]. Here, we develop a theory for a magnonic thermal Hall effect driven by many-body skew scattering. To exclude intrinsic effects, we consider a chiral ferromagnet with a single magnon band. The Dzyaloshinskii-Moriya interaction gives rise to many-body interactions that break time-reversal symmetry. Within the framework of the semi-classical Boltzmann equation, we show that a transverse magnon current arises from the skew scattering caused by the interference of three-magnon and four-magnon scattering channels. We estimate that this novel contribution to the thermal Hall effect can be as large as (or even larger than) the intrinsic contribution. Thus, we believe that our work will help better explain related experimental results.

[1] Czajka, P., Gao, T., Hirschberger, M. et al., Nat. Mater. 22, 36-41 (2023)

[2] S. Suetsugu, T. Yokoi, K. Totsuka, T. et al., Phys. Rev. B 105, 024415 (2022)

Keywords: Thermal Hall effect; Magnons; many-body interactions; magnetism