铁电体BaTiO3(001)表面电子结构的第一性原理研究

In this paper, the electronic properties of full-relaxed BaTiO3 (001) perfect surfaces and oxygen-vacancy surface are investigated by first-principles calculations. Caused by oxygen vacancies, some in-gap Ti 3d states at about -1.0 eV below the Fermi level are obtained in the Ti-terminated surface. For the Ba-terminated oxygen-vacancy surface, some in-gap Ti 3d states move into the bulk mid-gap region to become partial occupied, and two different chemical states of the Ba 5p states are observed, which are attributed to bulk perovskite Ba atoms and the relaxation of surface Ba atoms, respectively. These calculations are in agreement with the experimental data.