Comment on ``Conduction states in oxide perovskites: Three manifestations of Ti$^{3 +}$ Jahn-Teller polarons in barium titanate''

TL;DR

This paper comments on prior work about electronic structures in oxide perovskites, emphasizing the nature of oxygen vacancy levels and electron interactions, with implications for understanding conduction mechanisms.

Contribution

It provides a critical discussion on the electronic structure of oxygen vacancies, contrasting first principles calculations with experimental electroconductivity data.

Findings

Deep levels in oxygen vacancies supported by first principles

Electroconductivity data suggest different electron interaction energies

Highlights discrepancies between theoretical and experimental results

Abstract

In this comment to [S. Lenjer, O. F. Schirmer, H. Hesse, and Th. W. Kool, Phys. Rev. B {\bf 66}, 165106 (2002)] we discuss the electronic structure of oxygen vacancies in perovskites. First principles computations are in favour of rather deep levels in these vacancies, and Lenjer et al suggest that the electrons' interaction energy is negative, but data on electroconductivity are against.