Purity-dependent Lorenz number, electron hydrodynamics and electron-phonon coupling in WTe$_2$
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arXiv
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| Auteurs principaux: | , , , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866909293857472512 |
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| author | Xie, Wei Yang, Feng Xu, Liangcai Li, Xiaokang Zhu, Zengwei Behnia, Kamran |
| author_facet | Xie, Wei Yang, Feng Xu, Liangcai Li, Xiaokang Zhu, Zengwei Behnia, Kamran |
| contents | We present a study of electrical and thermal transport in Weyl semimetal WTe$_2$ down to 0.3 K. The Wiedemann-Franz law holds below 2 K and a downward deviation starts above. The deviation is more pronounced in cleaner samples, as expected in the hydrodynamic picture of electronic transport, where a fraction of electron-electron collisions conserve momentum. Phonons are the dominant heat carriers and their mean-free-path do not display a Knudsen minimum. This is presumably a consequence of weak anharmonicity, as indicated by the temperature dependence of the specific heat. Frequent momentum exchange between phonons and electrons leads to quantum oscillations of the phononic thermal conductivity. Bloch-Grüneisen picture of electron-phonon scattering breaks down at low temperature when Umklapp ph-ph collisions cease to be a sink for electronic flow of momentum. Comparison with semi-metallic Sb shows that normal ph-ph collisions are amplified by anharmonicity. In both semimetals, at cryogenic temperature, e-ph collisions degrade the phononic flow of energy but not the electronic flow of momentum. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2312_16178 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Purity-dependent Lorenz number, electron hydrodynamics and electron-phonon coupling in WTe$_2$ Xie, Wei Yang, Feng Xu, Liangcai Li, Xiaokang Zhu, Zengwei Behnia, Kamran Mesoscale and Nanoscale Physics Strongly Correlated Electrons We present a study of electrical and thermal transport in Weyl semimetal WTe$_2$ down to 0.3 K. The Wiedemann-Franz law holds below 2 K and a downward deviation starts above. The deviation is more pronounced in cleaner samples, as expected in the hydrodynamic picture of electronic transport, where a fraction of electron-electron collisions conserve momentum. Phonons are the dominant heat carriers and their mean-free-path do not display a Knudsen minimum. This is presumably a consequence of weak anharmonicity, as indicated by the temperature dependence of the specific heat. Frequent momentum exchange between phonons and electrons leads to quantum oscillations of the phononic thermal conductivity. Bloch-Grüneisen picture of electron-phonon scattering breaks down at low temperature when Umklapp ph-ph collisions cease to be a sink for electronic flow of momentum. Comparison with semi-metallic Sb shows that normal ph-ph collisions are amplified by anharmonicity. In both semimetals, at cryogenic temperature, e-ph collisions degrade the phononic flow of energy but not the electronic flow of momentum. |
| title | Purity-dependent Lorenz number, electron hydrodynamics and electron-phonon coupling in WTe$_2$ |
| topic | Mesoscale and Nanoscale Physics Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2312.16178 |