Comparison of electronic structures of ScAl 3 and ScRh 3: X-ray photoelectron spectroscopy and ab initio band calculation

Abstract

The electronic structure of ScAl 3 was compared with that of ScRh 3, where the electronegativity difference between the two elements in ScAl 3 is smaller than that in ScRh 3. The Al 2p and Sc 2p XPS for ScAl 3 have clear plasmon loss peaks as the Al 2p peak for the elemental Al, but Sc 3p spectrum for ScRh 3 has a featureless energy loss profile as the Sc 2p peak for the elemental Sc. The electronic structures in the valence and conduction band for ScAl 3 and ScRh 3 are calculated by ab initio band calculation method. The partial density of states of Sc 3d for ScAl 3 is higher than that for ScRh 3. The center of gravity of Sc 3d for ScAl 3 is located at lower binding energy side than that for ScRh 3. The electron density map for ScAl 3 shows that between Sc and Al atoms there is a ridge with two minimum points. On the other hand, Sc–Rh bond in ScRh 3 has one minimum point. It indicates that the bonds between Sc and Al atoms are highly covalent.