Reentrant Correlated Insulators in Twisted Bilayer Graphene at 25T ($2\pi$ Flux)

Abstract

Twisted bilayer graphene (TBG) is remarkable for its topological flat bands, which drive strongly-interacting physics at integer fillings, and its simple theoretical description facilitated by the Bistritzer-MacDonald Hamiltonian, a continuum model coupling two Dirac fermions. Due to the large moiré unit cell, TBG offers the unprecedented opportunity to observe reentrant Hofstadter phases in laboratory-strength magnetic fields near $25$T. This Letter is devoted to magic angle TBG at $2\pi$ flux where the magnetic translation group commutes. We use a newly developed gauge-invariant formalism to determine the exact single-particle band structure and topology. We find that the characteristic TBG flat bands reemerge at $2\pi$ flux, but, due to the magnetic field breaking $C_{2z}\mathcal{T}$, they split and acquire Chern number $\pm 1$. We show that reentrant correlated insulating states appear at $2\pi$ flux driven by the Coulomb interaction at integer fillings, and we predict the characteristic Landau fans from their excitation spectrum. We conjecture that superconductivity can also be re-entrant at $2\pi$ flux.

(See also "Observation of re-entrant correlated insulators and interaction driven Fermi surface reconstructions at one magnetic flux quantum per moire unit cell in magic-angle twisted bilayer graphene" by Das et al.)

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Cited by in corpus (31)

• Superconductivity and strong interactions in a tunable moiré quasiperiodic crystal
• Kondo Lattice Model of Magic-Angle Twisted-Bilayer Graphene: Hund's Rule, Local-Moment Fluctuations, and Low-Energy Effective Theory
• Phonons in magic-angle twisted bilayer graphene
• Symmetric Kondo Lattice States in Doped Strained Twisted Bilayer Graphene
• Dynamical correlations and order in magic-angle twisted bilayer graphene
• Hofstadter Topology with Real Space Invariants and Reentrant Projective Symmetries
• Magnetic Bloch Theorem and Reentrant Flat Bands in Twisted Bilayer Graphene at $2\pi$ Flux
• Quantum Monte Carlo sign bounds, topological Mott insulator and thermodynamic transitions in twisted bilayer graphene model
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• Replica Higher-Order Topology of Hofstadter Butterflies in Twisted Bilayer Graphene
• Topological heavy fermions in magnetic field
• Hofstadter spectrum of Chern bands in twisted transition metal dichalcogenides
• Interaction-driven Spontaneous Ferromagnetic Insulating States with Odd Chern Numbers
• Magnetic Bloch States at Integer Flux Quanta Induced by Super-moiré Potential in Graphene Aligned with Twisted Boron Nitride
• Correlated phases and topological phase transition in twisted bilayer graphene at one quantum of magnetic flux
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