Quasiparticle decay effects in the superconducting density of states: Evidence for d-wave pairing in the cuprates

Recent tunneling and photoemission data on the cuprate oxide superconductors may provide important information in choosing between proposed models for the superconducting order parameter in these materials. We show that corrections to the weak coupling mean-field approximation for a superconductor lead to different frequency thresholds for the spontaneous decay of the Bogoliubov quasiparticles for different order parameter symmetries and that these effects may be seen in the superconductor-insulator-superconductor tunneling conductance. Comparison with the recent data indicates that a dx2-y2, rather than an s-wave, order parameter is a likely candidate for describing the cuprates