The interactions of same-row oxygen vacancies on rutile TiO$_2$(110)

TL;DR

This paper develops an analytical dipolar-elastic model for oxygen vacancy interactions on rutile TiO₂(110), validated by DFT calculations and experimental STM data, enhancing understanding of vacancy distributions.

Contribution

It introduces a validated analytical interaction model for oxygen vacancies on rutile TiO₂(110), combining DFT calculations with experimental data.

Findings

Dipolar-elastic interaction holds for next-nearest neighbors and beyond.

Elastic interaction vanishes for adjacent vacancies, but electrostatic repulsion persists.

Model accurately predicts vacancy separation distribution matching STM experiments.

Abstract

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.