First-Principles Supercell Calculations of Small Polarons with Proper Account for Long-Range Polarization Effects

摘要

We present a density functional theory (DFT) based supercell approach formodeling small polarons with proper account for the long-range elastic responseof the material. Our analysis of the supercell dependence of the polaronproperties (e.g., atomic structure, binding energy, and the polaron level)reveals long-range electrostatic effects and the electron-phonon interaction asthe two main contributors. We develop a correction scheme for DFT polaroncalculations that significantly reduces the dependence of polaron properties onthe DFT exchange-correlation functional and the size of the supercell in thelimit of strong electron-phonon coupling. Using our correction approach, wepresent accurate all-electron full-potential DFT results for small polarons inrocksalt MgO and rutile TiO$_2$.