Destabilization of the Si(111) -bonded chain structure upon Cs adsorption

Contrary to previous knowledge, we have found an ordered 3×3R30° surface reconstruction on the cleaved Si(111) surface after room-temperature deposition of one monolayer of Cs. The preparation and characterization of this surface, and the dispersion of the lowest unoccupied surface-state band as measured with angle-resolved inverse photoemission spectroscopy are presented. The surface is observed at the saturation of the work function and found to be semiconducting. © 1989 The American Physical Society.