Role of intraband and interband pairings in two-band superconductors: deviation from BCS results

Abstract We study the stability of the intraband ( r =dd) and interband ( r =sd) couplings in the presence of the k -dependent hybridization in a two-band system. We calculate the critical temperature T c, r associated to both type of couplings, and we verified that there is a critical value of the hybridization V c , for which T c, r vanishes. Then we obtain the value of e r =2Δ ∗ r (0)/k B T c ,r and the isotope coefficients γ r showing that under some circumstances, one can obtain values for e r and γ r which differ considerably from standard BCS results for both Cooper pairings.