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Modeling the electrical conductivity in BaTiO3 on the basis of first-principles calculations

Erhart, Paul and Albe, Karsten (2008):
Modeling the electrical conductivity in BaTiO3 on the basis of first-principles calculations.
In: J. Appl. Phys., American Institute of Physics, pp. 044315-044315-9, 104, (4), [Online-Edition: http://jap.aip.org/resource/1/japiau/v104/i4/p044315_s1],
[Article]

Abstract

The dependence of the electrical conductivity on the oxygen partial pressure is calculated for the prototypical perovskite BaTiO3 based on data obtained from first-principles calculations within density functional theory. The equilibrium point defect concentrations are obtained via a self-consistent determination of the electron chemical potential. This allows one to derive charge carrier concentrations for a given temperature and chemical environment and eventually the electrical conductivity. The calculations are in excellent agreement with experimental data if an accidental acceptor dopant level of 10(17) cm(3) is assumed. It is shown that doubly charged oxygen vacancies are accountable for the high-temperature n-type conduction under oxygen-poor conditions. The high-temperature p-type conduction observed at large oxygen pressures is due to barium vacancies and titanium-oxygen divacancies under Ti- and Ba-rich conditions, respectively. Finally, the connection between the present approach and the mass-action law approach to point defect thermodynamics is discussed. (C) 2008 American Institute of Physics.

Item Type: Article
Erschienen: 2008
Creators: Erhart, Paul and Albe, Karsten
Title: Modeling the electrical conductivity in BaTiO3 on the basis of first-principles calculations
Language: English
Abstract:

The dependence of the electrical conductivity on the oxygen partial pressure is calculated for the prototypical perovskite BaTiO3 based on data obtained from first-principles calculations within density functional theory. The equilibrium point defect concentrations are obtained via a self-consistent determination of the electron chemical potential. This allows one to derive charge carrier concentrations for a given temperature and chemical environment and eventually the electrical conductivity. The calculations are in excellent agreement with experimental data if an accidental acceptor dopant level of 10(17) cm(3) is assumed. It is shown that doubly charged oxygen vacancies are accountable for the high-temperature n-type conduction under oxygen-poor conditions. The high-temperature p-type conduction observed at large oxygen pressures is due to barium vacancies and titanium-oxygen divacancies under Ti- and Ba-rich conditions, respectively. Finally, the connection between the present approach and the mass-action law approach to point defect thermodynamics is discussed. (C) 2008 American Institute of Physics.

Journal or Publication Title: J. Appl. Phys.
Volume: 104
Number: 4
Publisher: American Institute of Physics
Uncontrolled Keywords: ab initio calculations, barium compounds, carrier density, chemical potential, density functional theory, electrical conductivity, vacancies (crystal)
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Materials Modelling
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 28 Feb 2012 15:21
Official URL: http://jap.aip.org/resource/1/japiau/v104/i4/p044315_s1
Identification Number: doi:10.1063/1.2956327
Funders: This project was funded by the Sonderforschungsbereich 595 “Fatigue in functional materials” of the Deutsche Forschungsgemeinschaft.
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