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Liquid-to-liquid phase transition in pancake vortex systems

Joonhyun Yeo·M. A. Moore
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Abstract

We study the thermodynamics of a model of pancake vortices in layered superconductors. The model is based on the effective pair potential for the pancake vortices derived from the London approximation of a version of the Lawrence-Doniach model which is valid for extreme type-II superconductors. Using the hypernetted-chain (HNC) approximation, we find that there is a temperature below which multiple solutions to the HNC equations exist. By explicitly evaluating the free energy for each solution we find that the system undergoes a first-order transition between two vortex liquid phases. The low-temperature phase has larger correlations along the field direction than the high-temperature phase. We discuss the possible relation of this phase transition to the liquid-to-liquid phase transition recently observed in Y-Ba-Cu-O superconductors in high magnetic fields in the presence of disorder.

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Joonhyun Yeo, M. A. Moore. 2001-08-24. Liquid-to-liquid phase transition in pancake vortex systems. https://doi.org/10.1103/physrevb.65.144515

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