First-principles study of the drift and Hall mobilities of perovskite BaSnO3

Abstract

Barium stannate (${\mathrm{BaSnO}}_{3}$) is an emerging perovskite oxide with promising properties for many potential applications. One of the most outstanding properties is the high-room-temperature electron mobility. The extraordinary superior electronic transport performance has attracted great attention but the research is limited by semiempirical assumptions. In this work, the first-principles calculations are employed to study the electronic transport of ${\mathrm{BaSnO}}_{3}$ by solving the Boltzmann transport equation (BTE) with full information on electron, phonon, and electron-phonon interactions taken into account. The mode-resolved analyses of scattering rates show that the longitudinal optical (LO) phonons dominate the scattering processes not only at low but also at high carrier concentrations. As a consequence, the energy relaxation time approximation significantly underestimates the solution of BTE due to the divergent coupling coefficient of electrons and LO phonons. The drift and Hall mobilities are calculated in the framework of BTE in the presence of electric and magnetic fields. At low concentration limits, the room-temperature drift and Hall mobilities are 357 and $418\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{2}\phantom{\rule{0.16em}{0ex}}{\mathrm{V}}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$, respectively, while the Hall factor is temperature dependent with values between 1.06 and 1.17 in the temperature range of 100 K to 800 K. In the doping system with carrier concentration above $1\ifmmode\times\else\texttimes\fi{}{10}^{19}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$, the upper limit of drift mobility is $377\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{2}\phantom{\rule{0.16em}{0ex}}{\mathrm{V}}^{\ensuremath{-}1}\phantom{\rule{0.16em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$ at room temperature, and the Hall factor becomes smaller than 1, which cannot be revealed by the formula under the isotropic parabolic assumption at all, indicating the importance of magnetic transport calculation from ab initio based BTE.