Electronic and volumetric effects in ternary compounds of ytterbium

We present complete results of self-consistent electronic-structure calculations of Yb-based and Lu-based ternary intermetallic compounds, namely, YbCu4Ag, YbCu4Au, YbCu4Pd. and LuCu4Ag. All these materials show a characteristic peak in the optical conductivity at about 2-2.5 eV. From the analysis of the allowed interband transitions among the calculated bands at the Gamma point, we explain the origin of this peak. YbCu4Ag is a Kondo system with a high Kondo temperature. YbCu4-Au and -PJ order magnetically below 1 Ii We give an interpretation of the origin of the different degree of f-d hybridization observed experimentally in these Yb-based compounds.