Speaker
Description
We use dynamical mean-field theory to study the interplay of electron correlations and spontaneous symmetry-breaking in magic-angle twisted bilayer graphene. We find that there is no genuine Mott state—long-range order from spontaneous symmetry-breaking is essential to opening a gap at the Fermi level. We find that dynamic correlations strongly suppress ordering temperatures (by a factor of 10 compared to Hartree-Fock calculations). We characterise the momentum-resolved spectral functions and low energy quasiparticles as a function of filling in both the symmetry-broken and symmetric states. Our results provide a new understanding of the cascades seen in STM experiments as a sequence of Lifschitz transitions. Finally, we find a curious enhancement of correlations by order at certain values of doping close to integer filling.
