Regensburg 2016 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 15: Poster session I
MM 15.2: Poster
Montag, 7. März 2016, 18:00–20:00, Poster B3
Statics and dynamics of point defects in TiC — •Hossein Ehteshami1, Weiwei Sun2, and Pavel A. Korzhavyi1 — 1Materials Technology, Deptartment of Materials Science and Engineering, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden — 2Materials Theory, Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden
In this study, we present the results of a systematic ab initio study of point defects in titanium carbide. The electronic spectra and atomic structures for the metal and non-metal vacancies, interstitials, and antisite defects (including the split interstitial and split antisite conformations) are calculated within the generalized gradient approximation of density functional theory, using the projector augmented wave method as implemented in the Vienna Ab-initio Simulation Package VASP. In many cases the symmetric point defect configuration is found to be unstable agains a symmetry-breaking distortion via the Jahn-Teller mechanism. An enhanced stability of titanium dumbbells is obtained for sub-stoichiometric TiC where the dumbbels form clusters with the carbon vacancies. Possible migration pathways for point defects and their clusters are explored in order to create a database of possible mechanisms of self-diffusion in TiC. The obtained information about the electronic of point defects, as well as about their formation and migration energies, can be useful in experimental (spectroscopic) and theoretical (atomistic modeling) studies of TiC and related materials.