Electronic structure of Sb monolayers on the Mo(110) surface

We compare theory and experimental (LEED and EELS) studies of the atomic and electronic structure of adsorbed Sb layers on Mo(110). At half a monolayer coverage, Sb atoms occupy the "long-bridge" (hollow) sites forming the (1 x 2) film structure. At this coverage, a dramatic decrease of surface density of states in vicinity of Fermi level results in a quasi dielectric state of the surface. With increasing coverage, direct lateral interaction between Sb atoms becomes increasingly important and leads to push-out of some Sb atoms in the (2 x 3/2) surface unit cell from the adsorption sites that are favorable at lower coverages. Substantial overlap of orbitals of neighboring adatoms results in metallic state of adsorbed Sb film, as suggested from significant increase of DOS at Fermi level. In EEL spectra, the nonmetal to metal transition reveals itself also by appearance of the -7.8 eV peak, which may be explained by the interband transition from Sb s band to unoccupied p states above E-F. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.