Single domain Ca-induced reconstruction on vicinal Si(111)

High-quality vicinal Si(111) surfaces are used as templates to create single domains of the Si(111)3 x 1-Ca reconstruction which exhibit atomic chains parallel to Si steps. Scanning tunneling microscope images support the formation of honeycomb chains of Si atoms, rather than zigzag chains proposed in earlier models. Angle-resolved photoemission is used to map out the dispersion of valence band states parallel and perpendicular to the chains. A gap of approximate to0.9 eV is found below the Fermi level with both in-plane and out-of-plane polarization of the synchrotron light. The observed semiconducting behavior suggests that the honeycomb chain channel model proposed for the alkali-induced 3 x 1 reconstruction be modified for divalent alkaline earths, e.g. a 3 x 2 structure with 1/6 monolayer coverage. (C) 2002 Elsevier Science B.V. All rights reserved.