We describe strongly attractive carriers in cuprates in the framework of a simple quasi-one dimensional Hamiltonian with a local attraction. In contrast with the conventional BCS theory there are two energy scales, a temperature independent incoherent gap Δp and a temperature dependent coherent gap Δc(T) combining into one temperature dependent global gap Δ=(Δp2+Δc2)1/2. The temperature dependence of the gap and single particle (Giaver) tunnelling spectra in cuprates are quantitatively described. A framework for understanding of two distinct energy scales observed in Giaver tunnelling and electron-hole reflection experiments is provided.
@article{arxiv.cond-mat/0005315,
title = {Gap and subgap tunnelling in cuprates},
author = {A. S. Alexandrov and A. F. Andreev},
journal= {arXiv preprint arXiv:cond-mat/0005315},
year = {2009}
}