THE PHASE-DIAGRAM OF ANNEALED GE(111) GA

A study of the annealed phases of Ge(111)/Ga for coverages above 0.05 ML is presented. The surfaces are investigated by low-energy electron diffraction, scanning tunneling microscopy, and partly by photoemissio n and surface X-ray diffraction using synchrotron radiation. For Ga co verages beyond 0.05 ML and up to about 2 ML and annealing temperatures higher than 500 degrees C four different phases appear. They all can be characterized as being discommensurate. Surprisingly, no commensura te superstructure appears on annealed Ge(111)/Ga.