Band-edge positions in GW: Effects of starting point and self-consistency

We study the effect of starting point and self-consistency within GW on the band-edge positions of semiconductors and insulators. Compared to calculations based on a semilocal starting point, the use of a hybrid-functional starting point shows a larger quasiparticle correction for both band-edge states. When the self-consistent treatment is employed, the band-gap opening is found to result mostly from a shift of the valence-band edge. Within the non-self-consistent methods, we analyse the performance of empirical and nonempirical schemes in which the starting point is optimally tuned. We further assess the accuracy of the band-edge positions through the calculation of ionization potentials of surfaces. The ionization potentials for most systems are reasonably well described by one-shot calculations. However, in the case of TiO2, we find that the use of self-consistency is critical to obtain a good agreement with experiment.


Published in:
Physical Review B, 90, 16
Year:
2014
Publisher:
College Pk, American Physical Society
ISSN:
1098-0121
Laboratories:




 Record created 2014-12-30, last modified 2018-03-17


Rate this document:

Rate this document:
1
2
3
 
(Not yet reviewed)