A scanning tunnelling microscopic study was made of (110) surfaces. Various types of intrinsic defect were produced by treatment at temperatures above 1070K, under ultra-

high vacuum. These were mainly (001) single steps, (001) line defects, and O vacancies. Atomically resolved scanning tunnelling microscopic images made it possible to determine their geometrical structures. Together with additional data from voltage-dependent images, the present results were used to develop simple structural models for electrostatically neutral (001) single-steps on (110) surfaces and for (001) line defects. The latter consisted of Ti vacancies and O vacancies along the [001] direction.

S.Fischer, A.W.Munz, K.D.Schierbaum, W.Göpel: Surface Science, 1995, 337, 17-30