Electronic structure of RAuSn (R=Sc, Ce, Gd, Er, and Lu) investigated with x-ray photoelectron spectroscopy and band structure calculations

We have investigated the electronic structure of the intermetallic compounds ScAuSn, CeAuSn, GdAuSn, ErAuSn, and LuAuSn using x-ray photoelectron spectroscopy and band structure calculations. We find good general agreement between the experimental and calculated valence band spectra, provided that the spin-orbit interaction in the Au bands as well as correlation effects in the open rare-earth 4f shell are included in the calculations. The rare-earth 4f and Au 5d have well identified spectral features far away from the Fermi level. The spectral weight in the vicinity of the Fermi level is built up of mainly Au/Sn sp and rare-earth spd bands. We find an extremely low or vanishing spectral weight at the Fermi level for ScAuSn and LuAuSn, consistent with their semiconducting behavior as revealed by temperature dependent resistivity measurements