Local structural change caused by light irradiation on TiO2 (1 1 0) surface observed by scanning tunneling microscopy

Visible laser light (442 nm) irradiation created an atomic-scale structure on a rutile TiO2 (1 1 0)-(1 1) surface. The created bright structure, shaped like a bow tie, had an appearance of connecting two neighboring Ti [0 0 1] rows. The structure also showed dark areas in its front and in its back. The structure was interpreted as an oxygen deficiency on the (1 1) surface, and one of the dark spots around the structure as the oxygen atom displaced from its original position. The structure often appeared as a pair aligned along [1 1 0] direction, which could be viewed as a local (2 3) structure.