Antiferromagnetic interactions and the superconducting gap function

Radtke R. J., Liechtenstein A. I., Yakovenko V. M., Das Sarma S.

Univ Maryland Dept Phys Ctr Superconduct Res College Pk Md 20742
Max Planck Inst Festkorperforsch D-70569 Stuttgart Germany

Spin-fluctuation-mediated superconductivity is conventionally associated with d(x2-y2) pairing. We show that a generalized model of antiferromagnetic spin fluctuations in three dimensions may also yield a state with formal ''s-wave'' (A(1g)) symmetry but with line nodes at k(z) approximate to +/- pi/2c. We study this state within both BCS and Eliashberg theories using a realistic band structure and find that it is more stable than the d(x2-y2) (B-1g) state over a wide range of parameters. Thus, models of spin-fluctuation-mediated superconductivity must Consider both possibilities on an equal footing.

Physical Review B, 53 5137-5140, 1996.

Max-Planck Institut für Festkörperforschung;
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