Electron Mobilities in SrTiO$_3$ and KTaO$_3$: Role of Phonon Anharmonicity, Mass Renormalization and Disorder
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arXiv
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| Autori principali: | , , , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2024
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| _version_ | 1866913447324680192 |
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| author | Ranalli, Luigi Verdi, Carla Zacharias, Marios Evens, Jacky Giustino, Feliciano Franchini, Cesare |
| author_facet | Ranalli, Luigi Verdi, Carla Zacharias, Marios Evens, Jacky Giustino, Feliciano Franchini, Cesare |
| contents | Accurately predicting carrier mobility in strongly anharmonic solids necessitates a precise characterization of lattice dyndamics as a function of temperature. We achieve consistency with experimental electron mobility data for bulk KTaO$_3$ and SrTiO$_3$ above 150 K by refining the Boltzmann transport equations. This refinement includes incorporating temperature-dependent anharmonic phonon eigenfrequencies and eigenmodes into the electron-phonon interaction tensor, while maintaining the derivatives of the Kohn-Sham potential as computed in density functional perturbation theory. Using efficient machine-learned force fields and the stochastic self-consistent harmonic approximation, we accurately compute the dynamical matrices. At room temperature, the calculated mobility for SrTiO$_3$ exceeds experimental values by an order of magnitude, whereas the overestimation for KTaO$_3$ is way less pronounced. This discrepancy is explained through the more significant electron mass renormalization near the conduction band bottom due to anharmonic electron-phonon coupling and the presence of local disorder in SrTiO$_3$. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2407_18771 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Electron Mobilities in SrTiO$_3$ and KTaO$_3$: Role of Phonon Anharmonicity, Mass Renormalization and Disorder Ranalli, Luigi Verdi, Carla Zacharias, Marios Evens, Jacky Giustino, Feliciano Franchini, Cesare Materials Science Accurately predicting carrier mobility in strongly anharmonic solids necessitates a precise characterization of lattice dyndamics as a function of temperature. We achieve consistency with experimental electron mobility data for bulk KTaO$_3$ and SrTiO$_3$ above 150 K by refining the Boltzmann transport equations. This refinement includes incorporating temperature-dependent anharmonic phonon eigenfrequencies and eigenmodes into the electron-phonon interaction tensor, while maintaining the derivatives of the Kohn-Sham potential as computed in density functional perturbation theory. Using efficient machine-learned force fields and the stochastic self-consistent harmonic approximation, we accurately compute the dynamical matrices. At room temperature, the calculated mobility for SrTiO$_3$ exceeds experimental values by an order of magnitude, whereas the overestimation for KTaO$_3$ is way less pronounced. This discrepancy is explained through the more significant electron mass renormalization near the conduction band bottom due to anharmonic electron-phonon coupling and the presence of local disorder in SrTiO$_3$. |
| title | Electron Mobilities in SrTiO$_3$ and KTaO$_3$: Role of Phonon Anharmonicity, Mass Renormalization and Disorder |
| topic | Materials Science |
| url | https://arxiv.org/abs/2407.18771 |