Electronic structure of theSi(111)3×3R30°−Bsurface

Abstract

The plane-wave pseudopotential density functional theory (DFT) package FHI98MD has been used to optimize the geometry of the $\mathrm{Si}(111)\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}R30\ifmmode^\circ\else\textdegree\fi{}\ensuremath{-}\mathrm{B}{(S}_{5})$ configuration. The resultant geometry has been found to be in excellent agreement with recent experimental results. By calculating the band structure for the $\mathrm{B}{(S}_{5})$ configuration and carefully analyzing the nature of the wave functions in the vicinity of the Fermi energy, we have been able to identify the surface states along the various symmetry directions of the surface Brillouin zone (SBZ). The overall dispersion of both the occupied and unoccupied surface state bands is found to be in excellent agreement with the angle-resolved photoemission data. The theoretical calculations also predict the occurrence of two occupied surface state bands at the $\ensuremath{\Gamma}$ and M points of the SBZ. The splitting of these bands is predicted to be 0.27 eV and 0.35 eV, respectively, in good agreement with experiment.