We argue that Josephson tunneling between a conventional s-wave superconductor and an odd-parity (triplet) superconductor, with the conventional frequency 2eV/ℏ, is possible even when the boundary, represented by a tunneling Hamiltonian, is time-reversal symmetric. Thus, an observation or non-observation, of Josephson tunneling with frequency 2eV/ℏ is not a strict criterion for singlet or triplet superconductivity. This result is relevant for heavy fermion superconductors in which spin-orbit scattering is of central importance.
Paper: [Postscript] [PDF]
Unpublished Manuscript, Dec. 1985: A preliminary report of this work was given at the Int'l. Conf. on Magnetism and Magnetic Materials, held in San Francisco, August 1985. This paper was originally submitted to Physical Review B, but remains unpublished. It was widely distributed as a preprint and is referred to in a number of articles on Josephson tunneling, including the review articles on superconductivity in Heavy Fermion materials by Lee, et al. (1986) and by Sigrist and Ueda (1991). In this paper it is shown that the sign of the Josphson critical current depends on the relative orientation of the order parameter and interface. This is the basis for the pi junction interference experiments that have played such an important role in the discussions of the symmetry of the pairing state in the high Tc superconductors. The work of Geshkebein and Larkin on the same subject appeared in JETP months after this article was circulated.