The effects of N-doping and oxygen vacancy on the electronic structure and conductivity of PbTiO

By using spin-polarized density functional theory calculations,the electron density differences,band structures and density of states of p-type N-doped PbTiO;have been studied.In addition,the oxygen vacancy in N-doped PbTiO;is also discussed.After the nitrogen dopant is introduced into the crystal,the N-doped PbTiO;system is spin-polarized,the spin-down valance bands move to a high energy level and the Fermi energy level moves to the top of the valance bands,finally the band gap is narrowed.In this process,the N-doped PbTiO3 shows typical p-type semiconductor characteristics.When an oxygen vacancy and N impurity coexist in PbTiO;,there is no spin-polarized phenomenon.The conduction bands move downward and the acceptors are found to be fully compensated.The calculation results are mostly consistent with the experimental data.