X-dependent electronic structure of YbXCu4 (XÂ =Â Cd, In, Sn) investigated by hard X-ray photoemission spectroscopy

▶ Comparison of electronic structure of YbCdCu4 and YbSnCu4 with that of the valence transition compounds YbInCu4. ▶ The lowest binding energy of the Cu 2p3/2 level for YbInCu4. ▶ Excess conduction electrons at the Cu site play an important role for the valence transition of YbInCu4.