Structural, vibrational and quasiparticle properties of the Peierls semiconductor $\rm BaBiO_3$: a hybrid functional and self-consistent GW+vertex-corrections study
| Autor: | Franchini, C., Sanna, A., Marsman, M., Kresse, G. |
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| Rok vydání: | 2008 |
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| Druh dokumentu: | Working Paper |
| Popis: | $\rm BaBiO_3$ is characterized by a charge disproportionation with half of the Bi atoms possessing a valence 3+ and half a valence 5+. Because of 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 $\rm BaBiO_3$. The results obtained using GW (Green's function G and screened Coulomb potential W) based schemes on top of hybrid functionals, including fully 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. Comment: 5 pages, 5 figures |
| Databáze: | arXiv |
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