Surface segregation on Pt0.1Ni0.9(111) measured two layers deep by low-energy electron diffraction

Abstract

The authors measure the segregation of platinum at the (111) surface of the Pt0.1Ni0.9 single-crystal alloy by means of low-energy electron diffraction (LEED) and find that platinum is enriched to 30+or-4% in the first layer and depleted to 5+or-3% in the second; the corresponding relaxations of the interlayer spacings are 0+or-0.2% and -0.8+or-0.9%. They let the averaged t-matrix approximation mimic LEED and substitutional disorder, and use metric distances for fitting a structural model to the data.