The influence of (non-magnetic and magnetic) impurities on the transition temperature of a d-wave superconductor is studied anew within the framework of BCS theory. Pairing interaction decreases linearly with the impurity concentration. Accordingly Tc suppression is proportional to the (potential or exchange) scattering rate, 1/τ, due to impurities. The initial slope versus 1/τ is found to depend on the superconductor contrary to Abrikosov-Gor'kov type theory. Near the critical impurity concentration Tc drops abruptly to zero. Because the potential scattering rate is generally much larger than the exchange scattering rate, magnetic impurities will also act as non-magnetic impurities as far as the Tc decrease is concerned. The implication for the impurity doping effect in high Tc superconductors is also discussed.
ASJC Scopus subject areas
- Statistical and Nonlinear Physics
- Condensed Matter Physics