Identification of single-layer metallic structure of indium on Si(1 1 1).

We have studied the In/Si(1 1 1) ([Formula: see text])-hex and striped phases by low-energy electron diffraction (LEED) and angle-resolved photoelectron spectroscopy (ARPES). The two phases are formed by different processes, and hence the different names have been used conventionally. We, however, found that LEED I-[Formula: see text] curves of the two phases agree with each other, indicating that they have an identical atomic structure. Our ARPES measurement revealed that the ([Formula: see text])-hex phase has metallic surface states. The observed Fermi surface was found to be very similar to the theoretical one calculated for an indium single-layer model.