title: Defect calculations in semiconductors through a dielectric-dependent hybrid DFT functional: The case of oxygen vacancies in metal oxides.
abstract: We investigate the behavior of oxygen vacancies in three different metal-oxide semiconductors (rutile and anatase TiO2, monoclinic WO3, and tetragonal ZrO2) using a recently proposed hybrid density-functional method in which the fraction of exact exchange is material-dependent but obtained ab initio in a self-consistent scheme. In particular, we calculate charge-transition levels relative to the oxygen-vacancy defect and compare computed optical and thermal excitation/emission energies with the available experimental results, shedding light on the underlying excitation mechanisms and related materials properties. We find that this novel approach is able to reproduce not only ground-state properties and band structures of perfect bulk oxide materials but also provides results consistent with the optical and electrical behavior observed in the corresponding substoichiometric defective systems.
authors.affiliation: Department of Energy, Politecnico di Milano, via Ponzio 34/3, 20133 Milano, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Gerosa
authors.affiliation: Department of Energy, Politecnico di Milano, via Ponzio 34/3, 20133 Milano, Italy.
authors.forename: Carlo Enrico
authors.initials: CE
authors.lastname: Bottani
authors.affiliation: Dipartimento di Fisica dell'Università degli Studi di Milano and European Theoretical Spectroscopy Facility (ETSF), via Celoria 16, 20133 Milano, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Caramella
authors.affiliation: Dipartimento di Fisica dell'Università degli Studi di Milano and European Theoretical Spectroscopy Facility (ETSF), via Celoria 16, 20133 Milano, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Onida
authors.affiliation: Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 20125 Milan, Italy.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Di Valentin
authors.affiliation: Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, via R. Cozzi 55, 20125 Milan, Italy.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Pacchioni