On the nature of the superconducting gap in the cuprates

Recent experiments indicate that the excitation spectrum of the cuprates is characterised, in the superconducting state, by two energy scales: the “coherence energy” ∆c and the “pseudogap” ∆p. Here we consider a simple generalisation of the BCS model that yields exotic pairing and can describe, phenomenologically, the generic trends in the critical temperature Tc of cuprate superconductors. We use the model to predict the gap in the single-particle spectrum arising from the superconductivity and we find evidence that it corresponds to the lower of the two energy scales, ∆c, seen in the experiments. This supports the view that the origin of the pseudogap is not superconducting fluctuations. PACS numbers: 74.72.-h, 74.25.Dw, 74.62.Dh, 74.20.Rp, 74.62.Fj