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Theory of Josephson tunneling along the c-axis of YBCO

Robert Haslinger·Robert Joynt
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Abstract

The existence of Josephson tunneling has been demonstrated between YBa$_2$Cu$_3$O$_{7-δ}$ and Pb with the current flowing along the c-axis of YBa$_2$Cu$_3$O$_{7-δ}$. This is presumed to come from an s-wave component of the superconductivity in YBa$_2$Cu$_3$O$_{7-δ}$, perhaps induced by the orthorhombic distortion. This hypothesis by itself appears to be in contradiction with experiments on twinned samples whose tunneling current does not follow random statistics. We present a theory which depends on a competition between the intertwin d-wave coupling and a relatively enhanced s-wave component on the surface. This theory appears to explain, at least qualitatively, all observations made to date.

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Robert Haslinger, Robert Joynt. 1998-03-10. Theory of Josephson tunneling along the c-axis of YBCO. https://arxiv.org/abs/cond-mat/9803124

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