Structural, vibrational and quasiparticle properties of the Peierls semiconductor $\rm BaBiO_3$: a hybrid functional and self-consistent GW+vertex-corrections study
BaBiO3 is characterized by a charge disproportionation with half of the Bi atoms possessing a valence 3+ and half a valence 5+. Because of selfinteraction errors, local and semi-local density functionals fail to describe the charge disproportionation quantitatively, yielding a too small structural distortion and no band gap. Using hybrid functionals we obtain a satisfactory description of the structural, electronic, optical, and vibrational properties of BaBiO3. The results obtained using GW (Green's function G and screened Coulomb potential W) based schemes on top of hybrid functionals, including fully selfconsistent GW calculations with vertex corrections in the dielectric screening, qualitatively confirm the HSE picture but a systematic overestimation of the bandgap by about 0.4 eV is observed.
@article{arxiv.0803.0619,
title = {Structural, vibrational and quasiparticle properties of the Peierls semiconductor $\rm BaBiO_3$: a hybrid functional and self-consistent GW+vertex-corrections study},
author = {C. Franchini and A. Sanna and M. Marsman and G. Kresse},
journal= {arXiv preprint arXiv:0803.0619},
year = {2009}
}