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arXiv · 1811.07295

Stabilization of vortex-liquid state by strong pairing interaction

Kyosuke Adachi·Ryusuke Ikeda
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Abstract

We theoretically investigate qualitative features of the field-temperature ($H$-$T$) phase diagram of superconductors with strong attractive interaction lying in the BCS-BEC crossover regime. Starting with a simple attractive Hubbard model, we estimate three kinds of characteristic fields, i.e., the pair-formation field $H^*$, the vortex-liquid-formation field $H_\mathrm{c2}$, and the vortex-lattice-formation field $H_\mathrm{melt}$. The region between $H_\mathrm{c2}$ and $H_\mathrm{melt}$, as well as that between $H_\mathrm{c2}$ and $H^*$, is found to be enlarged as the interaction is stronger. In other words, a strong attractive interaction can stabilize both the vortex-liquid and preformed-pair regions. We also point out the expected particle-density dependence of the $H$-$T$ phase diagram.

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Kyosuke Adachi, Ryusuke Ikeda. 2019-02-15. Stabilization of vortex-liquid state by strong pairing interaction. https://doi.org/10.1103/physrevb.99.064508

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