CONSEQUENCES OF D-WAVE SUPERCONDUCTIVITY FOR HIGH-FREQUENCY APPLICATIONS OF CUPRATE SUPERCONDUCTORS

A number of recent experiments suggest that the superconducting ground state wave function in YBa2Cu3O7-delta (YBCO) has d-wave symmetry. Ho wever little attention has been given to the consequences of d-wave pa iring symmetry on applications of the cuprates. An intrinsic finite re sidual loss, approximately one order of magnitude below the lowest los ses measured in YBCO thin films at 10 GHz, is one important consequenc e. In addition, an unusual sensitivity to disorder, an intrinsic non-l inear power dependence, and unique mid-gap states associated with spec ific film textures and possibly twin boundaries, are also expected. We present our own attempts to identify these unique properties of d-wav e superconductors, and discuss how these results may dictate the ultim ate limitations of the cuprates in high frequency applications.