Interlayer hopping properties of electrons in layered metals

A formalism is proposed to study the electron tunneling between extended states, based on the spin-boson Hamiltonian previously used in two-level systems. It is applied to analyze the out-of-plane tunneling in layered metals considering different models. By studying the effects of in-plane interactions on the interlayer tunneling of electrons near the Fermi level, we establish the relation between departure from Fermi-liquid behavior driven by electron correlations inside the layer and the out of plane coherence. Response functions, directly comparable with experimental data are obtained.