Exotic superconductivity in graphene multilayers

  Erez Berg  
Weizmann Institute of Science

Recently, graphene multilayers have emerged as a rich platform to study quantum many-body physics. I will describe recent experiments in rhombohedral trilayer graphene (RTG), where superconductivity was recently discovered at the boundary between states with different patterns of spin and valley symmetry breaking. I will argue that several key experimental facts can be explained if the superconductivity is unconventional, and will present several theoretical routes to achieving such states in RTG. Motivated by the fact that one of the superconducting phases is a fully spin polarized triplet state, I will analyze the properties of this exotic phase. The topology of its order parameter space, that intertwines the phase of the superconducting condensate with the spin polarization, can lead to unusual phenomena, such as anomalous supercurrent dissipation and a fractional-period  ac Josephson effect.