Oxygen adatoms at SrTiO3(001): A density-functional theory study

TL;DR

This study uses density-functional theory to investigate oxygen adatoms on SrTiO3(001), revealing their bonding, diffusion barriers, and implications for oxide film growth.

Contribution

It provides detailed insights into the energetics and electronic structure of oxygen adatoms, highlighting their molecular formation and complex surface interactions.

Findings

Oxygen adatoms form peroxide-type species with surface lattice oxygen.

Diffusion barriers for adatoms are below 1 eV.

Weak binding at surface terminations may affect oxide film growth.

Abstract

We present a density-functional theory study addressing the energetics and electronic structure properties of isolated oxygen adatoms at the SrTiO3(001) surface. Together with a surface lattice oxygen atom, the adsorbate is found to form a peroxide-type molecular species. This gives rise to a non-trivial topology of the potential energy surface for lateral adatom motion, with the most stable adsorption site not corresponding to the one expected from a continuation of the perovskite lattice. With computed modest diffusion barriers below 1 eV, it is rather the overall too weak binding at both regular SrTiO3(001) terminations that could be a critical factor for oxide film growth applications.