Identifying the superconducting pairing state of high-Tcoxides by the Josephson effect

The Josephson junction consisting of high-${\mathit{T}}_{\mathit{c}}$ superconductor, normal metal, and high-${\mathit{T}}_{\mathit{c}}$ superconductor is studied microscopically using the quasiclassical theory. For a d-wave pairing state and certain crystal orientations of the two superconductors, the main Shapino step is found at V=hν/4e and the diffraction pattern has the form ${\mathit{I}}_{\max }$(Φ)=${\mathit{I}}_{\mathit{c}}$‖sin(2πΦ/${\mathrm{\Phi }}_0$)/(2πΦ/${\mathrm{\Phi }}_0$)‖. The experimental verification of this property can be used to distinguish unambiguously the possible d-wave pairing state in the high-${\mathit{T}}_{\mathit{c}}$ superconductors from the conventional s-wave or extended s-wave pairing states. Our result is also discussed in comparison with those obtained from other types of Josephson junctions.