We calculate the band structures of kesterite and stannite Cu2ZnSnS4 and Cu2ZnSnSe4, using a state-of-the-art self-consistent GW approach. Our accurate quasiparticle states allow to discuss: the dependence of the gap on the anion displacement; the key-role of the non-locality of the exchange-correlation potential to obtain good structural parameters; the reliability of less expensive hybrid functional and GGA+U approaches. In particular, we show that even if the band gap is correctly reproduced by hybrid functionals, the band-edge corrections are in disagreement with self-consistent GW results, which has decisive implications for the positioning of the defect levels in the band gap.
@article{arxiv.1105.4968,
title = {Band structures of Cu2nSnS4 and Cu2nSnSe4 from many-body methods},
author = {Silvana Botti and David Kammerlander and Miguel A. L. Marque},
journal= {arXiv preprint arXiv:1105.4968},
year = {2015}
}
Comments
accepted for publication in App. Phys. Lett. (2011)