Face dependent oxidation of CuAu using hyperthermal O molecular beam

Hashinokuchi, Michihiro*; Okada, Michio*; Tsuda, Yasutaka*; Makino, Takamasa*; Yoshigoe, Akitaka ; Teraoka, Yuden

The studies of the oxidation on Cu-Au alloy surfaces can provide great insights into the effect of alloying on the formation of protective layers. In our previous studies, it was found that the Au rich layer produced by Cu segregation during oxidation works as the protective subsurface layer even against a hyperthermal O beam with a kinetic energy of 2.3 eV. In order to clarify the face dependence of oxidation process, we studied the surface temperature dependence of oxidation on CuAu(110) using the hyperthermal O beam and the synchrotron radiation X-ray photoemission spectroscopy. The surface temperature dependence appeared in O 1s spectra suggests that the diffusion of Cu atom plays a crucial role in the oxidation of the open (110) surface. The Cu segregation enhanced at higher surface temperature may decrease the number density of surface Au atoms and accelerate the oxidation.