Honeycomb chain-channel (HCC) signature in the calcium-induced Si(111)-(3 x 2) surface

The electronic and structural properties of a calcium-induced chain system on Si(111) have been studied. Low-energy electron diffraction measurement clearly reveal a (3 x 2) periodicity and the Ca coverage is determined to be 1/6 monolayer. Angle-resolved photoemission measurement have been performed with two different light polarizations in order to study the symmetries of the surface states. In both polarizations no band crossing the Fermi level E-F is found. The three detected surface state bands are in good agreement with theoretical calculations in the honeycomb chain-channel (HCC) model for an insulating case.