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Magic angles and topology in twisted nodal superconductors

ORAL

Abstract

We propose twisted bilayers of two-dimensional nodal superconductors as a new platform to realize topological and correlated superconducting phases. We show that the Fermi velocity of the Dirac excitations in the Bogoliubov-De Gennes quasiparticle dispersion is strongly renormalized by the interlayer hopping, vanishing at a "magic angle”, where a pair of Dirac points merge into a quadratic band touching that is unstable to the formation of correlation-induced phases. We demonstrate that magnetic field, electric gating, and current bias can be used for versatile control of the system. In particular, we show that current bias can open a topological gap, with the system being characterized by a non-zero Chern number that is equal to the number of nodes. This produces a quantized thermal Hall effect with gapless thermal currents on the boundary.

Presenters

  • Pavel Volkov

    Rutgers University, Department of Physics and Astronomy, Center for Materials Theory,Rutgers University, Piscataway, New Jersey 08854, USA, Physics and Astronomy, Rutgers University

Authors

  • Pavel Volkov

    Rutgers University, Department of Physics and Astronomy, Center for Materials Theory,Rutgers University, Piscataway, New Jersey 08854, USA, Physics and Astronomy, Rutgers University

  • Jed Pixley

    Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Department of Physics, Rutgers, Rutgers University, Rutgers, The State University of New Jersey

  • Justin Wilson

    Rutgers University, New Brunswick, Department of Physics, Rutgers, Rutgers University