B. B. Kappes, W. B. Maddox, D. P. Acharya, P. Sutter, C. V. Ciobanu
Based on a dipolar-elastic model for oxygen vacancies on rutile (110), we evaluated analytically the overall energy of a periodic array of two vacancies and extracted the interaction parameters from total-energy density functional theory (DFT) calculations. Our calculations show that the dipole model holds for next-nearest neighbor vacancies and beyond. The elastic-dipolar interaction vanishes for adjacent vacancies, but they still experience an electrostatic repulsion. The proposed interaction model predicts a vacancy separation distribution that agrees well with that determined in our ultra-high vacuum scanning tunneling microscopy experiments, and provides a perspective for understanding earlier DFT reports.
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http://arxiv.org/abs/1301.2842
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