We present a study of VO2 in the rutile and monoclinic (M1) phases by means of all-electron full-potential LMTO GW calculation. Full frequency dependence and the off-diagonal matrix elements of the self-energy are taken into account. As a result of dynamical correlation, a satellite structure is found above the t2g quasiparticle peak but not below, in both the rutile and monoclinic phases. For the monoclinic structure, the insulating state is not obtained within the usual 1-shot GW calculation. We perform a simplified "self-consistent" GW scheme by adding a uniform shift to the conduction band levels and recalculating the quasiparticle wavefunctions accordingly. An insulating solution with a gap of approximately 0.6 eV is obtained, in agreement with experiments.
@article{arxiv.0804.0990,
title = {First-Principles Study of Correlation Effects in VO2: Peierls vs. Mott-Hubbard},
author = {R. Sakuma and T. Miyake and F. Aryasetiawan},
journal= {arXiv preprint arXiv:0804.0990},
year = {2008}
}