Effect of inhomogeneous deformation on the electronic structure of Sn[O.sub.2] and [Sn.sub.x][Sb.sub.1-x][O.sub.2] phases

The electronic structures of various phases in the Sn-Sb-[O.sub.2] system under pressure and under tetragonal, monoclinic, and orthorhombic deformation are studied. Calculations are performed using the first-principles pseudopotential method. It is established that Sn[O.sub.2] undergoes the following phase transitions under pressure: rutile-pyrite (17 GPa) and pyrite-fluorite (138 GPa). It is also found that doping Sn[O.sub.2] with Sb leads to a shift of the Fermi level to the conduction band and to additional resonant states below the valence band. Inhomogeneous deformation of [Sn.sub.x][Sb.sub.1-x][O.sub.2], x = = 1.00; 0.94; 0.88, at S