Berlin 2018 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 37: Electronic-Structure Theory: General II

O 37.5: Vortrag

Dienstag, 13. März 2018, 15:30–15:45, MA 141

First Principles Simulations of Small Polarons in Ionic Crystals — •Maria Dragoumi, Sebastian Kokott, Sergey Levchenco, Igor Ying Zhang, and Matthias Scheffler — Fritz Haber Institute of the Max Planck Society, Berlin, Germany

A small polaron can be modeled by a supercell with a hole or an electron in periodic boundary conditions. In order to correctly cover long-range contribution, very large supercells are often needed, which makes advanced first principles simulations prohibitively expensive to run. In this work, we propose a force-field corrected model to efficiently describe the lattice distortion due to the long range contribution in a reasonably small supercell model [1]. In this approach the electronic structure close to the center is treated accurately, on the theoretical levels of semilocal PBE, hybrid HSE06, and second-order Møller-Plesset perturbation theory, but taking into account the contribution of elastic distortion of the distant atoms by an appropriate model hamiltonian. The convergence behavior of long-range contribution in this hybrid strategy is examined and we apply this method to study the geometry distortion of the small polaron in MgO. The results are compared to other calculations using standard supercell models and to available experimental data.

[1] M. Scheffler, J.P. Vigneron, and G. B. Bachlelet, Phys. Rev. B 31, 6541 (1985).

[2] S. Kokott, S. V Levchenko, P. Rincke, and M. Scheffler, Submitted, arxiv:1710.03722 (2017).