($\d=0$) the magnetic moments of the localized $f$-electrons essentially behave as free spins, we thus obtain the typical Curie behavior with a $1/T$ dependence for the spin susceptibility. The slightly hole-doped regime does not show the behavior of a standard metal, namely $\chi_\mathrm{loc}$ keeps on increasing down to the lowest investigated temperature $T\simeq
10^{-3}D$ without any sign of saturation. The enhancement of the spin susceptibility signals the presence of unquenched local moments and can be associated to protracted screening effect.[@tahv1] Only for larger doping, the susceptibility saturates to large constant value at very low temperature.

![(Color online) Local spin susceptibility $\chi_\mathrm{loc}$ as a function of the temperature and increasing value of the hole doping. Data are from Lanczos ED (open symbols) and full ED (pluses, crosses and stars symbols) calculations. []{data-label="fig2.8"}](fig8.eps){width="45.00000%"}

The presence of enhanced low-$T$ spin susceptibility coexisting with a (bad) metallic behavior substantiates the idea that the hole-doped system can be regarded as formed by nearly free (incoherent) moments, and an underlying metallic host formed by the doped holes which are prevented from coherently delocalize by local coupling to $f$-moments. This interpretation leads us to estimate the coherence temperature $T_\mathrm{coh}$ from

We plot the resulting values, obtained with 