Effective Low-Energy Model for f-Electron Delocalization

We consider a periodic Anderson model (PAM) with a momentum-dependent interband hybridization that is strongly suppressed near the Fermi level. Under these conditions, we reduce the PAM to an effective low-energy Hamiltonian, H_eff, by expanding in the small parameter V₀/t (V₀ is the maximum interband hybridization amplitude and t is the hopping integral of the broadband). The resulting model consists of a t-J f-band coupled via the Kondo exchange to the electrons in the broadband. H_eff allows for studying the f-electron delocalization transition. The result is a doping-induced Mott transition for the f-electron delocalization, which we demonstrate by density-matrix renormalization group calculations.