Structure of the monoclinic Al13Fe4(010) complex metallic alloy surface determined by low-energy electron diffraction

Abstract : Complex metallic alloys having isolated transition-metal elements in the surface layer have been reported to work well as selective hydrogenation catalysts. We report an experimental determination of the surface structure of one such compound Al13Fe4(010). The structure was determined using low-energy electron diffraction. The best-fit structure terminates in a layer similar to the puckered bulk layer but lacking some of the Al and Fe atoms. Protruding Fe atoms are located in the middle of adjacent pentagonal Al formations, connected to each other by Al " glue " atoms. The top interlayer spacing is compressed relative to the bulk with oscillating relaxations observed for subsequent layers at the surface.