Decoupling superconductivity and correlated insulators in twisted bilayer graphene

Understand

When bilayer graphene is rotationally faulted to an angle $\theta\approx 1.1^\circ$, theory predicts the formation of a flat electronic band and correlated insulating, superconducting, and ferromagnetic states have all been observed at partial band filling.

• The proximity of superconductivity to correlated insulators has suggested a close relationship between these states, reminiscent of the cuprates where superconductivity arises by doping a Mott insulator.
• Here, we show that superconductivity can appear without correlated insulating states.
• While both superconductivity and correlated insulating behavior are strongest near the flat band condition, superconductivity survives to larger detuning of the angle.