Effect of Inhomogeneous Deformation on Electron Structure of the SnO₂ and Sn_xSb_1–xO₂ Phases

Abstract

Results of the electronic structure calculations of various phases of the system Sn–Sb–O₂ under hydrostatic pressure and tetragonal and monoclinic orthorhombic strains are presented. Calculations were performed using a first principle pseudopotential method. It is established that SnO₂ undergoes the following phase transitions under pressure: rutile–pyrite (17 GPa) and pyrite–fluorite (138 GPa). Also, it is found that the doping of SnO₂ with Sb leads to shifting the Fermi level to the conduction band and to appearing additional resonance states below the valence band. Inhomogeneous deformations of Sn_xSb_1–xO₂, x = 1.00; 0.94; 0.88, for strains δ ≤ 0.2, cause stress in the systems up to 6.2 GPa, depending on strain. An analysis of the electron density of states in the energy gap region of the deformed structures shows that the energy gap widens under tetragonal strain, and narrows under orthorhombic and monoclinic strains. The theoretical results can be used to interpret the tensoresistive properties of the thick films based on the Sn–Sb–O₂ system.