Study on electronic structure of C - Nb co- doped SnO₂ by first principles

First - principles theory is adopted to analyze the characteristics of semiconductor SnO₂ induced by C, Nb single doping and C-Nb co-doping, respectively. The stable structures, band structures and densities of states are calculated. The reasons for the magnetic properties of the doped systems are analyzed by means of the band structures and density of states. The results show that the stability of C-Nb codoped SnO₂ system is the best in C, Nb single doped and C-Nb co-doped SnO₂ systems, meanwhile, the their magnetic moments are 0 μ_B, 0.922 μ_B and 1.0 μ_B, respectively. The reason for the magnetism of the Nb doped SnO₂ system is the role of the d orbitals of Nb, and in the C-Nb co-doped SnO₂ system, the magnetism originates from the interaction between the s orbitals of Nb and the p orbitals of C. (authors)