N掺杂和氧空位对PbTiO3电子结构和导电性的影响研究

用第一性原理计算了P型N掺杂PbTiO3的电子密度差分、能带结构和态密度,讨论了氧空位对N掺杂PbTiO3性能的影响。在PbTiO3中掺杂N杂质后,PbTiO3的价带向高能级发生移动,费米能级进入价带顶部,带隙变窄,N掺杂PbTiO3表现出典型的P型半导体性能。当N掺杂PbTiO3中含有氧空位时,导带发生下移,受主被完全补偿。计算结果与实验数据相吻合。

The effects of N-doping and oxygen vacancy on the electronic structure and conductivity of PbTiO3

By using spin-polarized density functional theory calculations, the electron density differences, band structures and density of states of p-type N-doped PbTiO₃ have been studied. In addition, the oxygen vacancy in N-doped PbTiO₃ is also discussed. After the nitrogen dopant is introduced into the crystal, the N-doped PbTiO₃ 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 PbTiO₃, 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.