Predicting self-diffusion in metal oxides from first principles: The case of oxygen in tetragonal ZrO Citation

Citation Youssef, Mostafa, and Bilge Yildiz. "Predicting self-diffusion in metal oxides from first principles: The case of oxygen in tetragonal ZrO. Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Theoretical prediction of self-diffusion in a metal oxide in a wide range of thermodynamic conditions has been a long-standing challenge. Here, we establish that combining the formation free energies and migration barriers of all charged oxygen defects as calculated by density functional theory, within the random-walk diffusion theory framework, is a viable approach to predicting oxygen self-diffusion in metal oxides. We demonstrate this approach on tetragonal ZrO 2 by calculating oxygen self-diffusivity as a function of temperature and oxygen partial pressure or, alternatively, temperature and off-stoichiometry. Arrhenius analysis on the isobaric (or constant off-stoichiometry) self-diffusivities yields a spectrum of effective activation barriers and prefactors. This provides reconciliation for the wide scatter in the experimentally determined activation barriers and prefactors for many oxides.