Symmetry broken Chern insulators and magic series of Rashba-like Landau level crossings in magic angle bilayer graphene

Understand

Flat-bands in magic angle twisted bilayer graphene (MATBG) have recently emerged as a rich platform to explore strong correlations, superconductivity and mag-netism.

• However, the phases of MATBG in magnetic field, and what they reveal about the zero-field phase diagram remain relatively unchartered.
• Here we use magneto-transport and Hall measurements to reveal a rich sequence of wedge-like regions of quantized Hall conductance with Chern numbers C = +(-)1, +(-)2, +(-)3, +(-)4 which nucleate from integer fillings of the moire unit cell v = +(-)3, +(-)2, +(-)1, 0 correspondingly.
• We interpret these phases as spin and valley polarized Chern insulators, equivalent to quantum Hall ferro-magnets.