Abstract

We report the observation of robust Chern-zero fractional correlated insulating states at 1/3 fillings in twisted bilayer graphene with twist angles larger than the magic angle. These states dominate over integer-filling features, persist under perpendicular and parallel magnetic fields, and show behavior consistent with orbital geometric frustration arising from Wannier orbital shapes, Coulomb interactions, valley polarization, and exchange interactions. In a smaller-angle device, the data are consistent with a brick-wall charge-ordered state, while in a larger-angle device the response supports a tripled unit cell and an armchair-like phase. The results support a strong-coupling real-space description of fractional insulating states in tBLG.

Abstract

We report the observation of robust Chern-zero fractional correlated insulating states at 1/3 fillings in twisted bilayer graphene with twist angles larger than the magic angle. These states dominate over integer-filling features, persist under perpendicular and parallel magnetic fields, and show behavior consistent with orbital geometric frustration arising from Wannier orbital shapes, Coulomb interactions, valley polarization, and exchange interactions. In a smaller-angle device, the data are consistent with a brick-wall charge-ordered state, while in a larger-angle device the response supports a tripled unit cell and an armchair-like phase. The results support a strong-coupling real-space description of fractional insulating states in tBLG.

Abstract

We report the observation of robust Chern-zero fractional correlated insulating states at 1/3 fillings in twisted bilayer graphene with twist angles larger than the magic angle. These states dominate over integer-filling features, persist under perpendicular and parallel magnetic fields, and show behavior consistent with orbital geometric frustration arising from Wannier orbital shapes, Coulomb interactions, valley polarization, and exchange interactions. In a smaller-angle device, the data are consistent with a brick-wall charge-ordered state, while in a larger-angle device the response supports a tripled unit cell and an armchair-like phase. The results support a strong-coupling real-space description of fractional insulating states in tBLG.

Abstract

We report the observation of robust Chern-zero fractional correlated insulating states at 1/3 fillings in twisted bilayer graphene with twist angles larger than the magic angle. These states dominate over integer-filling features, persist under perpendicular and parallel magnetic fields, and show behavior consistent with orbital geometric frustration arising from Wannier orbital shapes, Coulomb interactions, valley polarization, and exchange interactions. In a smaller-angle device, the data are consistent with a brick-wall charge-ordered state, while in a larger-angle device the response supports a tripled unit cell and an armchair-like phase. The results support a strong-coupling real-space description of fractional insulating states in tBLG.