GAP-STATE FORMATION IN 2-DIMENSIONAL ORDERED BI LAYERS ON INAS(110)

The spectral density at the Fermi energy and the formation of adlayer- induced electronic states is studied by means of high energy resolutio n ultraviolet photoemission spectroscopy. A highly ordered (1x1)-Bi mo nolayer deposited on InAs(110) induces a well-resolved, occupied elect ronic state in the InAs surface gap, attributed to p-like dangling bon ds at the Bi atomic chains. Appropriate annealing of a Bi multilayer p roduces a (1x2)-symmetry stable phase. Evolution of the spectral densi ty close to the Fermi edge brings to light the metallicity of the (1 x 2)-Bi layer induced by Bi-Bi bonding in the atomic chains.