# DFT+DMFT study of oxygen vacancies in a Mott Insulator

## TL;DR

This study uses DFT+DMFT to investigate how oxygen vacancies affect the electronic properties and metal-insulator transition in LaTiO3, revealing the robustness of its Mott insulating state despite vacancy-induced bands.

## Contribution

It demonstrates that the Mott insulating state in LaTiO3 remains stable even with oxygen vacancies, using a combined DFT+DMFT approach with a minimal correlated subspace.

## Key findings

- Vacancy-related band forms below Ti-t2g bands
- Mott insulator remains robust despite vacancies
- Vacancy band stays fully occupied with Coulomb interactions

## Abstract

Oxygen vacancies are a common source of excess electrons in complex oxides. In Mott insulators these additional electrons can induce a metal-insulator transition (MIT), fundamentally altering the electronic properties of the system. Here we study the effect of oxygen vacancies in LaTiO3, a prototypical Mott insulator close to the MIT. We show that the introduction of oxygen vacancies creates a vacancy-related band immediately below the partially filled Ti-t2g bands. We study the effect of this additional band on the Mott MIT using a combination of density functional theory and dynamical mean-field theory (DFT+DMFT), employing a minimal correlated subspace consisting of effective Ti-t2g orbitals plus an additional Wannier function centered on the vacancy site. We find that the Mott insulating state in LaTiO3 is robust to the presence of the vacancy band, which remains fully occupied even in the presence of a local Coulomb repulsion.