We present a density functional theory (DFT) based supercell approach for modeling small polarons with proper account for the long-range elastic response of the material. Our analysis of the supercell dependence of the polaron properties (e.g., atomic structure, binding energy, and the polaron level) reveals long-range electrostatic effects and the electron-phonon interaction as the two main contributors. We develop a correction scheme for DFT polaron calculations that significantly reduces the dependence of polaron properties on the DFT exchange-correlation functional and the size of the supercell in the limit of strong electron-phonon coupling. Using our correction approach, we present accurate all-electron full-potential DFT results for small polarons in rocksalt MgO and rutile TiO2.
@article{arxiv.1710.03722,
title = {First-Principles Supercell Calculations of Small Polarons with Proper Account for Long-Range Polarization Effects},
author = {Sebastian Kokott and Sergey V Levchenko and Patrick Rinke and Matthias Scheffler},
journal= {arXiv preprint arXiv:1710.03722},
year = {2018}
}