Pairing symmetry of interacting fermions on twisted bilayer graphene superlattice

Understand

The pairing symmetry of an effective Hamiltonian for interacting fermions on a twisted bilayer graphene superlattice is studied with the determinant quantum Monte Carlo method.

• The model has the symmetry of a triangle lattice and a nearly-flat low energy band, features which underlie the magic-angle twisted bilayer graphene superlattice.
• We show that the low temperature phase is insulating at half-filling, even for relatively weak interactions.
• The natures of the spin and pairing correlations upon doping are determined, and exhibit an electron-hole asymmetry consistent with experiment.