Interaction Effect of Protons on Their Migration in Bulk Undoped Barium Zirconate Using Density Functional Theory

Abstract

The interaction effect of two protons on their migration in bulk barium zirconate was investigated to understand the difference between experimental and calculated energy barriers for proton migration using density functional theory. There were four different proton structure configurations in terms of proton interaction distance; symmetrically distorted, undistorted, symmetrically/asymmetrically distorted, and asymmetrically distorted. The asymmetrically distorted structure was obtained with the shortest distance between the two protons and was energetically the most stable. A high energy barrier of 0.41 eV was required for proton migration when a proton migrated near another proton owing to their repulsive interaction with each other and attractive interaction with neighboring oxygen ions. Therefore, the interaction between protons can contribute to reducing the difference between experimental and calculated energy barriers for proton migration in bulk barium zirconate. (c) 2012 The Japan Society of Applied Physics