Nematic superconductivity in twisted bilayer graphene

Twisted bilayer graphene displays insulating and superconducting phases caused by flattening of its energy band. In the superconducting dome near hole half-filling, the threefold lattice rotation symmetry is broken, and the superconductor is also a nematic. The authors argue that superconductivity can be properly described by a patch model near twelve Van Hove points and show that there is nearly equal attractive interaction in two different superconducting channels. They go on to explicitly demonstrate that when both orders develop, the superconducting state is also a nematic.