${\text{BaBiO}}_3$ is characterized by a charge disproportionation with half of the Bi atoms possessing a valence $3+$ and half a valence $5+$. Because of self-interaction errors, local- and semilocal-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 ${\text{BaBiO}}_3$. The results obtained using GW (Green’s function G and screened Coulomb potential W) based schemes on top of hybrid functionals, including fully self-consistent GW calculations with vertex corrections in the dielectric screening, qualitatively confirm the Heyd-Scuseria-Ernzerhof picture but a systematic overestimation of the band gap by about 0.4 eV is observed.

• Received 18 November 2009

DOI:https://doi.org/10.1103/PhysRevB.81.085213