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Electron Mobilities in SrTiO$ 3$ and KTaO$ 3$: Role of Phonon Anharmonicity, Mass Renormalization and Disorder by Ranalli, Luigi; Verdi, Carla; Zacharias, Marios; Evens, Jacky; Giustino, Feliciano; Franchini, Cesare is a scholarly article available to read on EtoBox.

What is Electron Mobilities in SrTiO$ 3$ and KTaO$ 3$: Role of Phonon Anharmonicity, Mass Renormalization and Disorder about?

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$_3$.

Author

Ranalli, Luigi; Verdi, Carla; Zacharias, Marios; Evens, Jacky; Giustino, Feliciano; Franchini, Cesare

Published

2024

Language

EN