DFT+DMFT study of oxygen vacancies in a Mott Insulator

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.

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Cited by in corpus (6)

• On the effect of charge self-consistency in DFT+DMFT calculations for complex transition metal oxides
• Importance of ligand on-site interactions for the description of Mott-insulators in DFT+DMFT
• Explicit demonstration of the equivalence between DFT+U and the Hartree-Fock limit of DFT+DMFT
• Oxygen Vacancies in Strontium Titanate: a DFT+DMFT study
• Single-site DFT+DMFT for vanadium dioxide using bond-centered orbitals
• Stability and diffusion of oxygen vacancies in LaNiO${}_3$: a DMFT study