Electronic interaction $U_{pp}$ on oxygen $p$ orbitals in oxides: Role of correlated orbitals on the example of UO$_2$ and TiO$_2$

TL;DR

This study investigates the impact of electronic interactions on oxygen p orbitals in oxides, highlighting the importance of orbital definitions and Wannier functions for accurate spectral and structural predictions.

Contribution

It provides detailed calculations of effective interactions and demonstrates how the choice of correlated orbitals influences the understanding of oxide properties.

Findings

Electronic interactions f, f, and p in UO and d, f, and p in TiO are quantified.

The role of f on oxygen p orbitals significantly affects spectral and structural properties.

Using Wannier functions yields more physical and reliable results.

Abstract

We carry out a detailed study of the role of electronic interaction on $p$ oxygen orbitals in a Mott insulator oxide (UO$_2$) and a charge transfer oxide (TiO$_2$). First, we calculate values of effective interactions \Uff, \Upp{} and $U_{fp}$ in UO$_2$ and \Udd{}, \Upp{} and $U_{dp}$ in TiO$_2$. Second, we analyze the role of electronic interactions \Upp{} on $p$ orbitals of oxygen in spectral and structural properties. Finally, we show that this role depends strongly on the definition of correlated orbitals and that using Wannier functions leads to more physical results for spectral and structural properties.