A theoretical study for the band gap energies of the most common silica polymorphs

Guler E., Ugur G., Ugur Ş., Guler M.

CHINESE JOURNAL OF PHYSICS, vol.65, pp.472-480, 2020 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 65
  • Publication Date: 2020
  • Doi Number: 10.1016/j.cjph.2020.03.014
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, INSPEC, zbMATH
  • Page Numbers: pp.472-480
  • Keywords: SiO2, Polymorph, DFTB, Electronic structure, Band gap energy, TIGHT-BINDING, SIO2, DENSITY, AL2O3, FORMS, TIO2
  • Gazi University Affiliated: Yes


Although numerous theoretical studies are available for the band gap energies of distinct silica (SiO2) polymorphs, some of the calculated results of these former studies still remain inconsistent and mostly disagree with the experimental data of the investigated polymorphs. To obtain more reasonable results, we have focused on the band gap energies of eleven different and more common silica polymorphs in this research by employing the self consistent charge (SCC) variant of the density functional based tight binding (DFTB) method. The surveyed eleven common silica polymorphs in this study are namely: alpha quartz, beta-quartz, alpha-tridymite, beta-tridyrnite, alpha-cristobalite, beta-cristobalite, alpha-moganite, beta-moganite, stishovite, coesite, and keatite Our obtained band gap energy results for alpha-quartz and stishovite are undoubtedly reasonable when compared with the existing experimental data of these polymorphs. As well, the maximum band gap energy is found to be as 9.70 eV for the beta-moganite polymorph, and the minimum band gap energy appears as 7.62 eV for the stishovite polymorph. Overall, the presently obtained results for the energy band gap of the considered silica polymorphs are satisfactory, and some of them are still waiting further experimental confirmation.