The 3×1 surface reconstruction of the Si(111) surface induced by adsorption of Li is studied with scanning tunneling microscopy (STM). Both filled- and empty-state STM images show arrays of atomic scale features with a 3×1 periodicity, but with different distributions of maxima within the unit cell. There are strong similarities with images of the Ag-induced 3×1 structure. STM images from both systems are compared with each other and discussed in terms of recent proposals that the metal atoms do not participate directly in the 3×1 long-range order.

• Received 3 August 1992

DOI:https://doi.org/10.1103/PhysRevB.46.13635