Abstract
Silica polymorphs have been analyzed, that are similar to the amorphous phase of SiO2; specifically, the α- and β-quartz, and the α- and β-cristobalite have been addressed. Two different ab initio methods have been used to calculate the full-band structure and the electronic properties of the polymorphs. In particular, the Hartree-Fock (HF) and Density-Functional Theory (DFT) approaches have been selected. A comparison of the energy-band branches and DOS shapes is reported, showing the similarities of the electrical properties that characterize the polymorphs under study. Finally, some relevant properties are compared for the analyzed set of polymorphs.