@article{79ece01e710a49d3ac634a51adff1c9d,
title = "Phase-sensitive tests of the symmetry of the pairing state in the high temperature superconductors --- evidence for dx2-y2 symmetry in YBCO",
abstract = "The most direct approach to determining the symmetry of the pairing state of the high temperature superconductors is to probe the spatial anisotopy of the relative phase of the order parameter. In contrast to magnitude measurements, the phase exhibits a clear distinction between the leading candidate states, the anisotropic s-wave state and the dx2-y2 wave state. Here, we present measurements of the phase coherence of bimetallic Josephson junctions and dc SQUIDs that show very strong evidence for the dx2-y2 pairing state and review other phase-sensitive experiments that have been conducted.",
author = "{Van Harlingen}, {D. J.} and Wollman, {D. A.} and Ginsberg, {D. M.} and Leggett, {A. J.}",
note = "Funding Information: Most experiments are sensitive only to the magnitude of the order parameter. For symmetries other than conventional isotropic s-wave, the magnitude exhibits a modulation with four-fold rotation symmetry. The reduced gap in some directions leads to an excess number of excited quasiparticles which shows up strongly in low temperature transport and tunneling spectra. Several experiments, including angle-resolved photoemission \[6\]R, aman scattering \[7\],a nd scanning tunneling microscopy \[8\]h ave probed the spatial anisotopy directly, finding evidence for the four-fold modulated magnitude in which the order parameter drops to no more than 20% of its maximum value along the diagonal directions. Measurements of the low temperature microwave penetration depth exhibit a linear temperature dependence down to about 2K, implying line nodes that are at most 2% of the full value \[9\]. Thus, the * Work supported by the Materials Research Laboratory under grant NSF-DMR89-20538. use of the MRL Microfabrication Laboratory.",
year = "1994",
month = dec,
doi = "10.1016/0921-4534(94)91328-5",
language = "English (US)",
volume = "235-240",
pages = "122--125",
journal = "Physica C: Superconductivity and its applications",
issn = "0921-4534",
publisher = "Elsevier B.V.",
number = "PART 1",
}