Twistronics” paradigm has been tremendously successful in realizing strongly correlated and topological phases of electrons in two-dimensional semiconductors or semimetals. In my talk, I will show that twisted bilayers of nodal superconductors allow a similar degree of control over the neutral quasiparticles in a superconductor.
I will demonstrate that the spectrum of the superconducting Dirac quasiparticles close to the gap nodes is strongly renormalized by twisting and can be controlled with magnetic fields, current, or interlayer voltage. In particular, the application of an interlayer current transforms the system into a topological superconductor with a Chern number equal to the number of nodes. Close to the “magic angle”, where the Dirac velocity of the quasiparticles is found to vanish, the interactions between them lead to a time-reversal symmetry breaking transition. A promising platform to observe these effects is provided by the high-Tc cuprates, and I will discuss the recent experimental results on twisted flakes of Bi2Sr2CaCu2O8+x.
Host: Meng Cheng
Please contact Taylor Dunnigan (taylor.dunnigan@yale.edu) for zoom connection information.