Electronic and geometric structure of Si(111)-(7 × 7) and Si(001) surfaces

The atomic origins of the intrinsic surface states of the Si(111)-(7 × 7) and Si(001) surfaces have been identified using the recently developed method of current imaging tunneling spectroscopy (CITS). On Si(111)-(7 × 7) three filled and two empty surface states are found and directly identified with atomic features of the dimer-adatom-stacking fault model. On Si(001) one filled and one empty state are observed and identified with atomic features of a dimer model. The STM images of Si(001) are shown to be dominated by the surface electronic structure rather than geometric structure. © 1987.