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arXiv · 2401.02872

Weak Coupling Theory of Magic-Angle Twisted Bilayer Graphene

Jihang Zhu·Iacopo Torre·Marco Polini·Allan H. MacDonald
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Abstract

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.

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Jihang Zhu, Iacopo Torre, Marco Polini, Allan H. MacDonald. 2024-01-05. Weak Coupling Theory of Magic-Angle Twisted Bilayer Graphene. https://doi.org/10.1103/physrevb.110.l121117

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