Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 36: Posters: Bio/organic Molecules on Surfaces, Graphene, Solid/liquid interfaces, Metal Substrates, Electronic Structure Theory

O 36.98: Poster

Dienstag, 1. April 2014, 18:30–22:00, P1

Intrinsic LiNbO3 point defects from total-energy difference and Slater-Janak transition state calculations — •Yanlu Li, Simone Sanna, and Wolf Gero Schmidt — Lehrstuhl für Theoretische Physik, Universität Paderborn, Paderborn, Germany

The formation energies and charge transition levels of the most relevant LiNbO3 point defects, i.e. Nb antisites and Li as well Nb vacancies are studied within density functional theory (DFT). In particular the effects of cell symmetry and the finite size error in calculations using periodic boundary conditions are examined. It is found that in particular the Nb vacancy causes a long-range strain field and requires large supercells for its adequate modeling. The extrapolation to infinitely large supercells decreases the relative stability of the Nb antisite and increases the relative stability of the Nb vacancy with respect to the Li vacancy, indicating the stability of VNb-5 in the wide range of Fermi level positions close to the conduction band minimum.