Thickness dependent structural and electronic properties of CuO adsorbed on SrTiO3(100): a hybrid density functional theory study

TL;DR

This study uses hybrid density functional theory to analyze how the structural and electronic properties of CuO vary with thickness when grown on SrTiO3(100), explaining experimental observations and emphasizing substrate effects.

Contribution

It provides a detailed theoretical explanation of CuO's properties on SrTiO3(100), highlighting the importance of substrate effects and local environment frustration.

Findings

Large Cu-O vertical distance explained by local environment frustration

Proper substrate modeling reproduces experimental valence band spectrum

CuO thickness of 3-3.5 unit cells matches experimental data

Abstract

We discuss the structural and electronic properties of tetragonal CuO grown on SrTiO3(100) by means of hybrid density functional theory. Our analysis explains the anomalously large Cu-O vertical distance observed in the experiments (~2.7 A) in terms of a peculiar frustration between two competing local Cu-O environments characterized by different in-plane and out-of-plane bond lengths and Cu electronic populations. The proper inclusion of substrate effects is crucial to understand the tetragonal expansion and to reproduce correctly the measured valence band spectrum for a CuO thickness of 3-3.5 unit cells, in agreement with the experimentally estimated thickness.