ELECTRONIC AND VOLUMETRIC EFFECTS IN TERNARY COMPOUNDS OF YTTERBIUM

We present complete results of self-consistent electronic-structure ca lculations of Yb-based and Lu-based ternary intermetallic compounds, n amely, YbCu4Ag, YbCu4Au, YbCu4Pd. and LuCu4Ag. All these materials sho w a characteristic peak in the optical conductivity at about 2-2.5 eV. From the analysis of the allowed interband transitions among the calc ulated bands at the Gamma point, we explain the origin of this peak. Y bCu4Ag is a Kondo system with a high Kondo temperature. YbCu4-Au and - PJ order magnetically below 1 Ii We give an interpretation of the orig in of the different degree of f-d hybridization observed experimentall y in these Yb-based compounds.