SurfaceScience21 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 22: Poster Session II: New methods II
O 22.1: Poster
Montag, 1. März 2021, 13:30–15:30, P
Enabling size convergence for surface calculations of materials exhibiting spontaneous polarization — •Su-Hyun Yoo1, Mira Todorova1, Liverios Lymperakis1, Chris Van de Walle2, and Jörg Neugebauer1 — 1Department of Computational Materials Design, Max-Planck-Insitut für Eisenforschung GmbH, Düsseldorf, Germany — 2Materials Department, UCSB, USA
The most common approach to describe surfaces in density-functional theory is the repeated slab geometry based on periodic boundary conditions. A common strategy to avoid artificial charge transfer from one side of the slab to the other when modelling semiconductor surfaces is to passivate partially filled surface dangling bonds at the backside of the slab. Using the example of wurtzite (0001) surfaces we demonstrate that conventionally used passivation schemes (e.g. pseudo H or surface reconstructions) break down for materials exhibiting spontaneous polarization. We have therefore developed a generalized passivation method that accounts for the effect of spontaneous polarization and correctly describes the asymptotic bulk limit for pyroelectric materials. It is robust and ensures quick convergence of total energies and electronic structure with respect to system size. The performance of our approach will be demonstrated using the example of wurtzite ZnO polar [1] and wurtzite GaN semi-polar surfaces [2].
[1] S. Yoo, M. Todorova, D. Wickramaratne, L. Weston, C. Van de Walle, and J. Neugebauer, NPJ Computational Materials (submitted).
[2] S. Yoo, L. Lymperakis, and J. Neugebauer (in preparation).