Fig. 4

Dependence of the low temperature valence on characteristic temperature scales. The deviation of the Yb valence from 3+ at low temperatures, Δn_h(0), is plotted against a the characteristic temperature scale of the valence changes, T_v, extracted from the data shown in Fig. 3, and b the Kondo energy scale, T_K, obtained from thermodynamic measurements. Data points taken from previous reports in the literature^{13,14,15,16, 19} are shown in shaded colors. The dashed lines are guides to the eye. The data show that Δn_h(0) scales with T_K as expected, over several orders of magnitude, while T_v does not scale with Δn_h(0) or T_K and is very similar in all investigated Yb Kondo lattices