Superconductors, Orbital Magnets, and Correlated States in Magic Angle Bilayer Graphene

Understand

Superconductivity often occurs close to broken-symmetry parent states and is especially common in doped magnetic insulators.

• When twisted close to a magic relative orientation angle near 1 degree, bilayer graphene has flat moire superlattice minibands that have emerged as a rich and highly tunable source of strong correlation physics, notably the appearance of superconductivity close to interaction-induced insulating states.
• Here we report on the fabrication of bilayer graphene devices with exceptionally uniform twist angles.
• We show that the reduction in twist angle disorder reveals insulating states at all integer occupancies of the four-fold spin/valley degenerate flat conduction and valence bands, i.e.