Surface structure and composition of the alloy Au3Pd(100) determined by LEED and ion scattering spectroscopy

The (100) surface of the alloy Au,Pd has been investigated by crystallograp hic LEED and ion scattering spectroscopy to determine the structure and com position of the first three atomic layers. The observed LEED pattern corres ponds to the bulk truncated structure of the substitutionally disordered Au 3Pd alloy. No significant relaxations of the first three layers have been f ound. Surface segregation of Au has been found by both methods, indicating pure Au in the topmost layer. The second layer is slightly depleted in Au ( c(Au,2) = 0.6 +/- 0.2).