Atomic-scale structure of the SrTiO3(001)-c(6x2) reconstruction: Experiments and first-principles calculations

TL;DR

This study combines experimental techniques and first-principles calculations to elucidate the atomic structure of the complex c(6x2) reconstruction on SrTiO3(001) surfaces formed at high temperatures.

Contribution

It presents a detailed atomic model of the SrTiO3(001)-c(6x2) surface reconstruction based on multiple experimental and computational methods, revealing its short-range order and structural motifs.

Findings

Atomic model consistent with experimental data

Presence of non-periodic TiO2 units on the surface

Simulated STM images match experimental observations

Abstract

The c(6x2) is a reconstruction of the SrTiO3(001) surface that is formed between 1050-1100oC in oxidizing annealing conditions. This work proposes a model for the atomic structure for the c(6x2) obtained through a combination of results from transmission electron diffraction, surface x-ray diffraction, direct methods analysis, computational combinational screening, and density functional theory. As it is formed at high temperatures, the surface is complex and can be described as a short-range ordered phase featuring microscopic domains composed of four main structural motifs. Additionally, non-periodic TiO2 units are present on the surface. Simulated scanning tunneling microscopy images based on the electronic structure calculations are consistent with experimental images.