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arXiv · 2310.06220

Slope of $H_{c2}$ close to $T_c$ versus the size of the Cooper pairs: The role of disorder in Dynes superconductors

František Herman·Richard Hlubina
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Abstract

The size of the Cooper pair $ξ_{\rm pair}$ is one of the basic characteristics of a superconductor, but it is not possible to measure it directly. It might be argued that $ξ_{\rm pair}$ can be determined from the value $ξ_{\rm slope}$ extracted from the measurement of the slope of $H_{c2}$ close to $T_c$. Taking into account both pair-conserving and pair-breaking scattering on impurities within the recently developed theory of Dynes superconductors, we perform an explicit calculation of $ξ_{\rm pair}$ and $ξ_{\rm slope}$. We show that the two quantities agree only in clean superconductors. In particular, when the pair-breaking disorder approaches the quantum critical point, $ξ_{\rm pair}$ stays finite, whereas $ξ_{\rm slope}$ diverges.

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František Herman, Richard Hlubina. 2023-10-20. Slope of $H_{c2}$ close to $T_c$ versus the size of the Cooper pairs: The role of disorder in Dynes superconductors. https://arxiv.org/abs/2310.06220

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