The relationship between the normal state Fermi liquid scattering rate and the superconducting state

International audienceMany superconductors show a low temperature electrical resistivity of Fermi liquid type ρ =AT2. We show empirically that there exists a relationship between A and Tc when both vary under an external parameter, such as pressure. The more resistive the compound the higher the Tc. Through the analysis of Landau theory of FL, we find that it is a general feature of FL, due to the fact that the scattering that is the main cause of τ is the same one that bounds the pairs that condensed at Tc. We devise a method that allows the determination of the coupling constant λ, which is validated through application to 3He-'s superfluid transitions and τ's extracted from different properties. This method works for conventional superconductors, but fails with heavy fermions