Reduced effect of impurities on the universal pairing scale in the cuprates

摘要

We consider the effect of nonmagnetic impurities on the onset temperature T~* for the d-wave pairing in spin-fluctuation scenario for the cuprates. We analyze intermediate coupling regime when the magnetic correlation length ξ/a>1 and the dimensionless coupling u is O(1). In the clean limit, T~*≈0.02v _f/a in this parameter range and weakly depends on ξ and u. We found numerically that this universal pairing scale is also quite robust with respect to impurities: the scattering rate Γ_(cr) needed to bring T~* down to zero is about four times larger than in weak coupling, in good quantitative agreement with experiments. We provide analytical reasoning for this result.