LDA + U and hybrid functional calculations for defects in ZnO, SnO2, and TiO2
Article first published online: 15 DEC 2010
Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
physica status solidi (b)
Volume 248, Issue 4, pages 799–804, April 2011
How to Cite
Janotti, A. and Van de Walle, C. G. (2011), LDA + U and hybrid functional calculations for defects in ZnO, SnO2, and TiO2. Phys. Status Solidi B, 248: 799–804. doi: 10.1002/pssb.201046384
- Issue published online: 24 MAR 2011
- Article first published online: 15 DEC 2010
- Manuscript Accepted: 2 NOV 2010
- Manuscript Revised: 1 NOV 2010
- Manuscript Received: 13 JUL 2010
- density functional theory;
- point defects
We describe and compare defect calculations based on density functional theory within the local density approximation (LDA), the orbital-dependent LDA + U, and using hybrid functionals. Limitations of the LDA in describing defect formation energies and transition levels are discussed, followed by corrections based on the LDA + U, and the use of the hybrid functional of Heyd, Scuseria, and Ernzerhof (HSE). The band-gap error in LDA leads to large uncertainties not only in defect transition levels but also in formation energies.
LDA + U provides a partial correction to the band gap and, when combined with LDA, provides an accurate method for predicting transition levels. Formation energies obtained from the LDA + U/LDA approach depend on the ability of LDA + U to correctly describe the position of the band edges on an absolute energy scale. Although computationally demanding, HSE is demonstrated to be a reliable method for predicting structure and electronic properties of semiconductors, including transition levels and formation energies of defects.