Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 17: Poster Session
MM 17.21: Poster
Montag, 26. März 2012, 17:00–19:00, Poster B
Towards kinetic Monte-Carlo simulations with ab initio accuracy — •Martin Leitner1, Tobias C. Kerscher1,2, Stefan Müller2, and Raimund Podloucky1 — 1University of Vienna, Institute of Physical Chemistry, Vienna, Austria — 2Hamburg University of Technology, Institute of Advanced Ceramics, Hamburg, Germany
For the Ni–Al and Fe–Al alloy system we present the first steps towards kinetic Monte-Carlo (KMC) simulations with ab initio accuracy. Many body interactions which describe the energetics of both the local minima and migration states are included by cluster expansions (CE) in the framework of the UNCLE code [1].
In this model approach single atoms jump to vacant nearest-neighbor sites and have to overcome configuration dependent migration barriers. According to transition state theory (TST) jump rates are then derived by the energy difference between initial and saddle point state. The KMC simulations require a) vacant lattice sites, which enforce a ternary CE for a binary compound, and b) the configuration dependent height of the saddle points, which have to be calculated and included in the CE.
We discuss different aspects of jump profiles in the respective systems computed by density functional theory (DFT) calculations.
The support of FWF project 4110 (ViCoM) is acknowledged.
[1] D. Lerch et al., Modelling Simul. Mater. Sci. Eng. 17 (2009), 055003