Josephson effect in the cuprates: microscopic implications

R. Hlubina

paper

Josephson effect in the cuprates: microscopic implications

arXiv:cond-mat/0210516

Abstract

In the tunnel limit, the current-phase relation of Josephson junctions can be expanded as $I (ϕ) = I_{1} sin ϕ + I_{2} sin 2 ϕ$ . Standard BCS theory predicts that $I_{1} R_{N} \sim Δ/ e$ and $I_{2} / I_{1} \sim D$ , where $R_{N}$ is the resistance of the junction in the normal state, $Δ$ is the superconducting gap, and $D ≪ 1$ is the junction transparency. In the cuprates, the experimental value of $I_{1} R_{N}$ ( $I_{2} / I_{1}$ ) is much smaller (larger) than the BCS prediction. We argue that both peculiarities of the cuprates can be explained by postulating quantum fluctuations of the pairing symmetry.

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