AN STM STUDY OF THE INSB(100)-C(8X2) SURFACE

Atomic resolution scanning tunneling microscopy (STM) images of InSb(100) prepared by in situ treatment of several cycles of low energy argon ion bombardment and annealing have been obtained. The STM images demonstrate how the structural quality of the surface improves dramatically with repeated bombardment and annealing cycles. After annealing to 625 K, atomically flat terraces were obtained over areas in excess of 1000 angstrom X 1000 angstrom and low energy electron diffraction (LEED) studies at room temperature revealed a sharp, stable c(8 X 2) pattern. Atomic resolution images indicate (4 X 1) unit cells in which occupied lone pair orbitals of Sb atoms in the second layer are imaged. The data obtained is consistent with the structural model presented for this surface on the basis of high resolution core level photoemission by John et al. [Phys. Rev. B 39 (1989) 1730] in which 3/4 of a monolayer of In dimers are on top of a complete monolayer-Sb-terminated surface.