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.
*P.A.V. acknowledges the Postdoctoral Fellowship support from the Rutgers University Center for Materials Theory. This work was also supported by Air Force Office of Scientific Research under Grant No. FA9550-20-1-0136 (J.P.).
–
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