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arXiv · 1610.04166

Unusual boundary effect on coherency of two-band superconductivity

Artjom Vargunin·Küllike Rägo·Teet Örd
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Abstract

We demonstrate that the healing of two-band superconductivity near the surface of the system is governed by length scales which are drastically different from correlation lengths. Similar to the one-band case, one of the characteristic lengths diverges at critical temperature $T_c$, while another one shows unusual behaviour having singularity at $T_{c+}<T_c$. By moving away from the boundary, these scales approach coherence lengths in the bulk state, where the divergence at $T_{c+}$ is removed by arbitrary weak interband coupling. Such a boundary-driven modification in coherency affects proximity phenomenon. We show that critical temperature of binary NS system can exhibit an inflection near $T_{c+}$ as two-band superconducting layer becomes thinner.

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Artjom Vargunin, Küllike Rägo, Teet Örd. 2016-10-13. Unusual boundary effect on coherency of two-band superconductivity. https://doi.org/10.1016/j.physleta.2017.08.010

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