Josephson Scanning Tunneling Spectroscopy in d_(x~2-y~2)-XVae Superconductors: A Probe for the Nature of the Pseudogap in the Cuprate Superconductors

摘要

Recent advances in the development of Josephson scanning tunneling spectroscopy (JSTS) have opened a new path for the exploration of unconventional superconductors. We demonstrate that the critical current I-c measured via JSTS, images the spatial form of the superconducting order parameter in d(x2)-d(y2)-wave superconductors around defects and in the Fulde-Ferrell-Larkin-Ovchinnikov state. Moreover, we show that I-c probes the existence of phase-incoherent superconducting correlations in the pseudogap region of the cuprate superconductors, thus providing unprecedented insight into its elusive nature. These results provide the missing theoretical link between the experimentally measured I-c and the spatial structure of the superconducting order parameter.