Giant Eliashberg enhancement of superconductivity in flat bands

ORAL

Abstract

The enhancement of superconductivity under appropriate electromagnetic radiation due to redistribution of quasiparticles into a more favorable nonequilibrium configuration is called Eliashberg effect. Here, we investigate the Eliashberg effect in flat band superconductors. While the superconductivity in flat bands is established by non-trivial winding of wavefunction of the slow-moving electrons, the Eliashberg enhancement is completely determined by the density of states which for flat bands is peaked in a narrow range of energies. We show that this large density of states in flat band materials can mediate a drastic enhancement of superconductivity when the material is irradiated with a light of frequency under pair breaking limit and band width. Assuming BCS coupling, we illustrate this enhancement in flat bands of twisted bilayer graphene. This opens new possibilities of nonequilibrium phenomena driven by peaked density of states in flat band superconductors, e.g., superfluid density and supercurrent.

*This work is supported by the Department of Energy BES under award number DE-SC0022277 as well as by the Quantum Science Center (QSC), a National Quantum Information Science Center of the U.S.Department of Energy (DOE) on probing quantum matter. We also acknowledge Grant No. GBMF8048 from the Gordon and Betty Moore Foundation.

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Presenters

  • Arpit Arora

    • University of California, Los Angeles

Authors

  • Arpit Arora

    • University of California, Los Angeles

  • Jonathan B Curtis

    • UCLA
    • University of California, Los Angeles

  • Prineha Narang

    • College of Letters and Science, University of California, Los Angeles (UCLA), CA, USA.
    • University of California Los Angeles
    • College of Letters and Science, University of California, Los Angeles (UCLA)
    • UCLA
    • University of California, Los Angeles
    • College of Letters and Science, University of California, Los Angeles
    • Harvard University