It has been claimed that the absence of the bilayer splitting in the high-temperature superconductor YBCO is a strong experimental indication that there are no coherent quasiparticles present in the CuO planes. We study a pair of strongly correlated planes which are connected by a hopping transfer integral t⊥ in the limit of large in-plane coordination number. The effect of the correlation is incorporated in a dynamical mean-field theory, where the Weiss field is determined by a two-site Hubbard Hamiltonian. We have solved this problem by numerical techniques and present results for the spectral function ρ for relevant parameters of the model. For small t⊥ we find the coherent hoping between planes to be proportional to the in-plane quasiparticle renormalisation.
@article{arxiv.cond-mat/9707051,
title = {Possible explanation for the absence of bilayer splitting in YBCO},
author = {H. Monien and N. Elstner and A. J. Millis},
journal= {arXiv preprint arXiv:cond-mat/9707051},
year = {2008}
}