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Unconventional Superconductivity in Semiconductor Artificial Graphene

ORAL

Abstract

Unconventional superconductivity featuring large pairing energies has attracted immense interest, yet tractable microscopic theories have proven elusive. A major breakthrough has been the advent of twisted bilayer graphene (TBG), which serves as a simple model system to `look under the hood' of unconventional superconductivity. We propose a new model, within current experimental reach, to investigate the microscopics of strong--binding superconductivity. Our proposed device is semiconductor artificial graphene, a two dimensional electron gas overlaid with a periodic potential. We demonstrate that this system realises a new mechanism for pairing, whereby the topology of the Dirac points gives rise to an attraction in the $p+ip$ channel. The pairing interaction, which originates from charge dynamics on the interlocking sublattices, dominates due to antiscreening, and -- in contrast to graphene -- can be strongly enhanced through device engineering. The unconventional superconducting gap provides a realisation of a Fulde-Ferrell-Larkin-Ovchinnikov state. The pairing strength is similar to TBG, and within the accuracy of our calculations we find $T_c$ up to 20 K for InAs heterostructures.

Presenters

  • Tommy Li

    Freie Univ Berlin

Authors

  • Tommy Li

    Freie Univ Berlin

  • Harley Scammell

    Harvard University

  • Julian P Ingham

    Boston University