2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/24559The out-of-plane hopping in layered metals with strong electronic correlation is analyzed theoretically. By studying the effects of in-plane interactions on the interlayer tunnelling we investigate one of the oldest unresolved problems of high-T$_c$ cuprates, the so-called bilayer splitting. The strong electron-electron interactions within each layer reduce the quasiparticle weight, and modify the hopping between layers. We analyze the effect of the in-plane correlations on the interlayer hopping using a Renormalization Group scheme already applied to the problem of interlayer coherence . The bilayer band splitting acquires a significant temperature and doping dependence, and can be completely suppressed when the Fermi energy coincides with a Van Hove singularity.contrbution submitted to SNS04SuperconductivityMaterials ScienceMany body effects on $c$- axis properties: out of plane coherence and bilayer splittingtext