Twisted bilayer graphene near the magic angle is known to have a cascade of insulating phases at integer filling factors of the low-energy bands. In this Letter we address the nature of these phases through an unrestricted, large-scale Hartree-Fock calculation on the lattice that self-consistently accounts for all electronic bands. Using numerically unbiased methods, we show that Coulomb interactions produce ferromagnetic insulating states at integer fillings ν ∈ [−3, 3] with maximal spin polarization MFM = 4 − |ν|. We find that the ν = 0 state is a pure ferromagnet, whereas all other insulating states are spin-valley polarized. At odd filling factors |ν| = 1, 3 those states have a quantum anomalous Hall effect with Chern number C = 1. Except for the ν = 0, −2 states, all other integer fillings have insulating phases with additional sublattice symmetry breaking and antiferromagnetism in the remote bands. We map the metal-insulator transitions of these phases as a function of the effective dielectric constant. Our results establish the importance of large-scale lattice calculations to faithfully determine the ground states of twisted bilayer graphene at integer fillings.

@article{
  title = {Strongly interacting phases in twisted bilayer graphene at the magic angle},
  author = {Adhikari, Khagendra and Seo, Kangjun and Beach, K. S. D. and Uchoa, Bruno},
  journal = {Physical Review B},
  volume = {110},
  issue = {12},
  pages = {L121123},
  numpages = {7},
  year = {2024},
  month = {Sep},
  publisher = {American Physical Society},
  doi = {10.1103/PhysRevB.110.L121123},
  url = {https://journals.aps.org/prb/abstract/10.1103/PhysRevB.110.L121123}
}