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arXiv · 1307.3955

A permutation invariant collective variable to track and drive vacancy dynamics in simulations of solids

Jan M. Knaup·Michael Wehlau·Thomas Frauenheim
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Abstract

Vacancy dynamics in oxides are vital for understanding redox reactions and resulting memristive effects or catalytic activity. We present a method to track and drive vacancies which we apply to metadynamics simulation of oxygen vacancies (V$_{\mathrm{O}}$) in rutile, demonstrating its effectiveness. Using the density functional based tight binding method, it is possible to explore the free energy hyperplane of oxygen vacancies in TiO$_{2}$. We show that the migration of V$_{\mathrm{O}}$ in TiO$_{2}$ is governed by the jump with the higherst number of realizations. Free energy profiles are consistent with minimum energy paths.

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Jan M. Knaup, Michael Wehlau, Thomas Frauenheim. 2013-07-15. A permutation invariant collective variable to track and drive vacancy dynamics in simulations of solids. https://doi.org/10.1103/physrevb.88.220101

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