the system develops a coherent Kondo resonance signature of the insulator-metal transition.

![(Color online) Left panel: renormalization constant $Z$ as a function of the doping $\d=|3-n_\mathrm{tot}|$. Data are from Lanczos ED at $T=0$, $U=2$, $\tpd=0.9$ and increasing size of the effective bath $N_s=8$ (diamonds, circles) and $10$ (triangles, squares). Right panel: moment-moment correlation $-\bra m_{zp}\cdot m_{zf}\ket$ as a function of the doping $\d$ in the hole doped regime. Data are from full ED calculations (see Appendix \[apx1\]) for $T=0.008$ and for the same model parameters.[]{data-label="fig2.2"}](fig3.eps){width="45.00000%"}

In the following we shall briefly review the formation of a correlated metallic state by hole doping[@sordi07; @sordi09]. Without loss of generality, we fix the energy of the correlated orbitals at the Fermi level $\ed0=0$ and $\ep0=-1$, so that $\Delta=1$. For $U=\tpd=0$ the model describes a system with completely filled conduction band $n_p=2$ and half-filled correlated orbitals with $n_f=1$. For finite values of the hybridization the correlated electrons can move with an effective hopping of the order of $t_{\rm
eff}\simeq\tpd^2/\Delta$, corresponding to the indirect delocalization through the conduction band (see top panel of ). The hybridization modifies the orbitals occupation, pushing a substantial amount of the $p$-electron states to the Fermi level, so that $n_p<2$ 