Where do the coherence peak singularities in the linear density of states lie for d-wave and extended s-wave pairing symmetries? In particular, what is the value of the gap between the coherence peaks in both cases in terms of pairing amplitude $\Delta$?
Given dispersion : $E_{k}=\sqrt{(\epsilon_{k}-\mu)^2+\Delta_{k}^{2}}$ where, $\Delta_{k}=\Delta(\cos{k_{x}}\pm \cos{k_{y}})$ for extended s-wave or d-wave symmetries.
And, $\epsilon_{k}=-2t(\cos{k_{x}}+\cos{k_{y}})$ as for simple square lattice.
