Phase transition of In/Si(111)-4×1 surface studied with low-energy electron diffraction

Abstract

The structural phase transition of an In/Si(111) surface was examined by low-energy electron diffraction (LEED). The transition temperature between the room-temperature 4×1 structure and low-temperature 8×2 structure was determined from the changes in the LEED intensity of the half-order (×2), eighth-order (8×), and fourth-order (4×) spots with temperature. The transition temperatures determined independently from three sets of LEED beam spots were within 1 K. The differently prepared In/Si(111)−4×1 surfaces, which had similar LEED quality at room temperature, showed variations of the transition temperature. The differences in the measured transition temperatures were attributed to the effects of the additional In adatoms remaining on the surface during the formation of a 4×1 reconstruction. The In adatoms suppress the condensation of the (8×2) phase, decreasing the phase transition temperature and rounding the otherwise sharp transition.