Atomic and electronic structures of the group-IV elements on Si(111)-(root 3x root 3) surface

17th International Vacuum Congress/13th International Conference on Surface Science/International Conference on Nanoscience and Technology -- JUL 02-06, 2007 -- Stockholm, SWEDENWOS: 000275655200255We have examined the Si(111) surface with 1/3 monolayer of group-IV elements within the abinitio density functional theory We have considered two possible threefold-c oordinated sites for the atom adsorption: (i) H-3 site (this site is directly above a fourth-layer Si atom and (ii) T-4 site (directly above a second-layer Si atom). For the atoms Ge, Sn, and Pb, the T-4 position always gives the most stable configuration, comparing with the H-3 site. The calculated energy difference between T-4 and H-3 for Pb, Ge, and Sn, is 0.32 eV, 0.59 eV, and 0.41eV, respectively. We have also presented electronic band structure and orbital character of the surface states of the Sn/Si(111)-(root 3x root 3)surface.Swedish Vacuum SocTurkish State Planning Organization [2001K120590]; Gazi University; BAP [05/2006-19, 05/2007-41]This work was supported by Turkish State Planning Organization (Project Number: 2001K120590). M. C gratefully acknowledges Gazi University for the financial support under BAP project 05/2006-19 and 05/2007-41