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arXiv · 1902.10897

Origin of flat-band superfluidity on the Mielke checkerboard lattice

M. Iskin
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Abstract

The Mielke checkerboard is known to be one of the simplest two-band lattice models exhibiting an energetically flat band that is in touch with a quadratically dispersive band in the reciprocal space, i.e., its flat band is not isolated. Motivated by the growing interest in understanding the origins of flat-band superfluidity in various contexts, here we provide an in-depth analysis showing how the mean-field BCS correlations prevail in this particular model. Our work reveals the quantum-geometric origin of flat-band superfluidity through uncovering the leading role by a band-structure invariant, i.e., the so-called quantum metric tensor of the single-particle bands, in the inverse effective mass tensor of the Cooper pairs.

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M. Iskin. 2019-02-28. Origin of flat-band superfluidity on the Mielke checkerboard lattice. https://doi.org/10.1103/physreva.99.053608

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