Angle-dependent planar thermal Hall effect by quasi-ballistic phonons in black phosphorus
| Autor: | Li, Xiaokang, Guo, Xiaodong, Zhu, Zengwei, Behnia, Kamran |
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| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | The origin of the phonon thermal Hall effect in insulators is a matter of ongoing debate. The large amplitude of the signal in an elemental non-magnetic solid, such as black phosphorus (BP) calls for a minimal mechanism with no role for spin degree of freedom. Here, we show that a longitudinal heat flow generates a transverse temperature gradient in BP even when the magnetic field, the heat current and the thermal gradient lie in the same plane. The long phonon mean-free-path leaves little room for scattering by point-like symmetry breaking defects. We argue that the angular dependence of the signal can be accounted for as a sum of two sinusoidal components each peaking when the magnetic field is parallel to a high symmetry axis. Anharmonicity and finite thermal expansion emerge as indispensable ingredients for a planar Hall signal. We identify the torque exerted by magnetic field on traveling electric dipolar waves as a possible microscopic driver. Comment: 6 pages, 4 figures, Supplemental Materials included |
| Databáze: | arXiv |
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