A surface analysis of CuAu alloy by leed and Auger electron spectroscopy

Surface structures and compositions of the CuAu alloys have been investigated, which were prepared by depositing gold on (110) and (111) surfaces of copper and by subsequent heating. By this method the structure of alloy surfaces corresponding to different compositions can be observed by LEED. A series of the LEED patterns, streak, (1 × 2), (1 × 1)I, complex, c(3 × 1), (1 × 1)II, (2 × 2) and (1 × 1) have been observed on the (110) surface with decreasing gold composition. On the (111) surface (1 × 1) pattern, weak (2/√3 × 2/√3)R30° and (2 × 2) patterns are observed. The mean surface composition is determined by analysing the data of Auger electron spectroscopy. Most surface periodicities observed are different from those expected if one passes a mathematical plane through the crystal (unreconstructed surface).