Electronic structure of the (001) surface of reduced SrTiO3

Electronic structures of reduced SrTiO3 surfaces are calculated by the use of non-norm conserving pseudopotential method. Oxygen vacancies are introduced on the top TiO2 layer of the (001) surface forming a regular View the MathML source supercell structure, as is proposed by the experimental observation. The band structures of the reduced surfaces have metallic features though the ideal surface has a semiconducting feature. Simulated STM images show that the oxygen vacancy is bright, and the shape of it is almost a circle. These properties as well as the calculated local density of states compare fairly well with the recent STM and STS observation.