High-resolution photoelectron spectroscopy study of Kondo metals: SmSn 3 and Sm 0.9 La 0.1 Sn 3

We performed a high-resolution photoelectron spectroscopy study on the Kondo metals SmSn 3 and Sm 0.9 La 0.1 Sn 3 . The experimental results are compared with calculations of density of state performed within the local density approximation plus the dynamical mean-field theory. The theory is found to reproduce the experimental valence-band spectra well. In both SmSn 3 and Sm 0.9 La 0.1 Sn 3 the bulk Sm valence is nearly trivalent, with a small fraction of divalent component. Resonant photoelectron spectroscopy indicates a decrease in the Kondo effect in the diluted system Sm 0.9 La 0.1 Sn 3 .