Generalizedη-pairing models and transition temperature in flat-band superconductors

ORAL

Abstract

Certain flat band tight-binding models have exact η-pairing ground states in which superconductivity can be analytically studied.  We generalize the η-pairing models to include generalized bipartite crystalline lattices [1], extending the flat-band superconducting models in [2] to realistic materials.  Our formalism allows for an analytic calculation of charge +1 and +2 excitations above the ground state, the superfluid weight, and a perturbative calculation of the maximum transition temperature and the location of the van Hove singularity.  We apply our results in the context of recent work performed in flat band superconductors such as twisted trilayer graphene [3], demonstrating the need for modifications to BCS theory in the presence of strong coupling.

[1] Calugaru et al., arXiv:2106.05272

[2] Tovmasyan et al., PRB 94, 245149 (2016)

[3] Hao et al., Science Vol. 371, No. 6534 (2021)

*B.A.B. and A.C. were supported by the ONR Grant No. N00014-20-1-2303, DOE Grant No. DESC0016239, the Schmidt Fund for Innovative Research, Simons Investigator Grant No. 404513, the Packard Foundation, the Gordon and Betty Moore Foundation through Grant No. GBMF8685 towards the Princeton theory program, and a Guggenheim Fellowship from the John Simon Guggenheim Memorial Foundation. Further support was provided by the NSF-MRSEC Grant No. DMR-1420541 and DMR-2011750, BSF Israel US foundation Grant No. 2018226, and the Princeton Global Network Funds. JHA is supported by a Marshall Scholarship funded by the Marshall Aid Commemoration Commission.

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Presenters

  • Aaron Chew

    • Princeton University

Authors

  • Aaron Chew

    • Princeton University

  • Jonah Herzog-Arbeitman

    • Princeton University

  • Andrei B Bernevig

    • Princeton University