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arXiv · 2407.08449

Coherence length and quantum geometry in a dilute flat-band superconductor

M. Iskin
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Abstract

To explore the influence of quantum-geometric effects on the Ginzburg-Landau coherence length in a dilute flat-band superconductor, we adopt a BCS-BEC crossover approach to the multiband pyrochlore-Hubbard model near the critical temperature for superconductivity. Our self-consistent formulation for this three-dimensional lattice benchmarks very well against the so-called zero-temperature coherence length, demonstrating the monotonic decay of the coherence length to zero as the interaction strength increases. Additionally, we show that the effective mass of the many-body bound states (i.e., Cooper pairs) is nearly identical to that of the lowest-lying two-body bound states in the dilute flat-band limit.

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M. Iskin. 2024-07-11. Coherence length and quantum geometry in a dilute flat-band superconductor. https://doi.org/10.1103/physrevb.110.144505

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