Triple-domain effects on the electronic structure of Pb/Si(111)-(√7 x √3): Density-functional calculations

Electronic structure of the Pb/Si(111)-(root 7 x root 3) surface has been studied by using density-functional theory calculations for a representative structural model with a coverage of 1.2 ML Our calculations do not reproduce all the bands reported in an angle-resolved photoemission spectroscopy (ARPES) study, but we find that this discrepancy could be resolved by taking into account the effect of the triple-domain structure of the (root 7 x root 3) surface samples. We also find that, while the calculated Fermi surface for a single-domain (root 7 x root 3) surface bears a (root 7 x root 3) periodicity, the overlap of the Fermi surfaces for three different (root 7 x root 3) domains reveals an effective (1 x 1) periodic pattern similar to the (1 x 1) Fermi surface measured for the (root 7 x root 3) surface. Thus, the unusual (1 x 1) pattern appearing in the measured Fermi surface is not likely due to any strong (1 x 1) potential in the (root 7 x root 3) surface as was speculated in the ARPES study. (C) 2010 Elsevier B.V. All rights reserved.