Strong correlations occur in magic-angle twisted bilayer graphene (MATBG) when the octet of flat moir\'e minibands centered on charge neutrality (CN) is partially occupied. The octet consists of a single valence band and a single conduction band for each of four degenerate spin-valley flavors. Motivated by the importance of Hartree electrostatic interactions in determining the filling-factor dependent band structure, we use a time-dependent Hartree approximation to gain insight into electronic correlations. We find that the electronic compressibility is dominated by Hartree interactions, that paramagnetic states are stable over a range of density near CN, and that the dependence of energy on flavor polarization is strongly overestimated by mean-field theory.
@article{arxiv.2401.02872,
title = {Weak Coupling Theory of Magic-Angle Twisted Bilayer Graphene},
author = {Jihang Zhu and Iacopo Torre and Marco Polini and Allan H. MacDonald},
journal= {arXiv preprint arXiv:2401.02872},
year = {2024}
}