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MA: Fachverband Magnetismus
MA 5: Focus Session: Magnetic Phenomena from Phonon Chirality and Angular Momentum I (joint session MA/TT)
MA 5.6: Vortrag
Montag, 17. März 2025, 12:15–12:30, H20
Extrinsic Phonon Thermal Hall Effect — •Dimos Chatzichrysafis1, Robin Richard Neumann1,2, and Alexander Mook1 — 1Johannes Gutenberg-Universität, Mainz, Germany — 2Martin-Luther-Universität Halle-Wittenberg, Germany
The thermal Hall effect is a developing tool to investigate charge-neutral excitations, exposing the quantum many-body ground state of correlated materials. Since a sense of chirality for the energy carriers is necessary for the generation of a thermal Hall effect, it is natural to expect that quasiparticles of magnetic excitations are responsible for the Hall transport. This conventional wisdom has been recently challenged in experiments [1] which revealed a universal character of the thermal Hall effect independent on the magnetic texture and the lattice structure, even in systems where magnetism is completely absent. This finding asks for the re-investigation of the role of phonons in the thermal Hall effect.
Here, we develop a theory for a phononic thermal Hall effect where the source of chirality is given by the presence of the molecular Berry phase. As a toy model we study a non-magnetic system on a Bravais square lattice. We go beyond the intrinsic mechanism [2] usually studied in literature and consider the contribution of different possible extrinsic sources of phonon Hall transport. Our results demonstrate that phonon thermal Hall effects can be native to very generic systems.
[1] Xiaobo Jin et al, arXiv:2404.02863
[2] Takuma Saito et. al, Phys. Rev. Lett. 123, 255901, December 2019
Keywords: thermal Hall effect; chiral phonons; phonon Hall effect; extrinsic Hall effect