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Anomalous Behavior of the Upper Critical Field in Extreme Type-II Superconductors at Low Temperatures

Sasha Dukan·Oskar Vafek
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Abstract

We present a detailed numerical calculation of the upper critical field $H_{c2}(T)$ for a bulk extreme type-II superconductor. Particular emphasis is placed on the high-field, low-temperature regime of the HT-phase diagram. In this regime it is necessary to go beyond the standard semi-classical theory and include the effects of Landau quantization of the electronic motion on the superconducting state. The presence of Landau level quantization induces an upward curvature in $H_{c2}(T)$ at $\sim 10%$ of $T_{c0}$ for those superconducting systems in which the slope of $H_{c2}(T)$ at $T_{c0}$ is $\geq $ 0.2 Tesla/Kelvin. We construct a simple analytical model that can account for this behavior based on the renormalization of the BCS coupling constant by the off-diagonal pairing of electrons on Landau levels.

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Sasha Dukan, Oskar Vafek. 1998-10-22. Anomalous Behavior of the Upper Critical Field in Extreme Type-II Superconductors at Low Temperatures. https://doi.org/10.1016/s0921-4534(98)00595-4

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