Interaction-Enhanced Topological Hall Effects in Strained Twisted Bilayer Graphene

Abstract

We analyze the effects of the long-range Coulomb interaction on the distribution of Berry curvature among the bands near charge neutrality of twisted bilayer graphene (TBG) closely aligned with hexagonal boron nitride (hBN). Due to the suppressed dispersion of the narrow bands, the band structure is strongly renormalized by electron-electron interactions, and thus, the associated topological properties of the bands are sensitive to filling. Using a Hartree formalism, we calculate the linear and nonlinear Hall conductivities, and find that for certain fillings, the remote bands contribute substantially to the Hall currents while the contribution from the central bands is suppressed. In particular, we find that these currents are generically substantial near regions of energies where the bands are highly entangled with each other, often featuring doping-induced band inversions. Our results demonstrate that topological transport in TBG/hBN is substantially modified by electron-electron interactions, which offer a simple explanation to recent experimental results.

7 + 7 pages, 4 + 5 figures. Comments are very appreciated!

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Cited by in corpus (12)

• Nonlinear anomalous Hall effects probe topological phase-transitions in twisted double bilayer graphene
• Strain induced quasi-unidimensional channels in twisted moiré lattices
• Non-linear Hall Effects: Mechanisms and Materials
• 3/2 magic-angle quantization rule of flat bands in twisted bilayer graphene and relationship with the Quantum Hall effect
• Electronic properties of twisted bilayer graphene suspended and encapsulated with hexagonal boron nitride
• Imaging Coulomb interactions and migrating Dirac cones in twisted graphene by local quantum oscillations
• Berry Curvature Spectroscopy from Bloch Oscillations
• Roses in the Nonperturbative Current Response of Artificial Crystals
• Designing Moire Patterns by Shearing
• Second-Order Conductivity Probes a Cascade of Singularities in a Moiré Superlattice
• Straintronics and twistronics in bilayer graphene
• Moiré-driven equilibrium of perturbations in moiré systems