Layer-Dependent Interaction Effects in the Electronic Structure of Twisted Bilayer Graphene Devices

Near the magic angle, strong correlations drive many intriguing phases in twisted bilayer graphene (tBG) including unconventional superconductivity and chern insulation. Whether correlations can tune symmetry breaking phases in tBG at intermediate (greater than or similar to 2 degrees) twist angles remains an open fundamental question. Here, using ARPES, we study the effects of many-body interactions and displacement field on the band structure of tBG devices at an intermediate (3 degrees) twist angle. We observe a layer- and doping-dependent renormalization of bands at the K points that is qualitatively consistent with moire models of the Hartree-Fock interaction. We provide evidence of correlation-enhanced inversion symmetry-breaking, manifested by gaps at the Dirac points that are tunable with doping. These results suggest that electronic interactions play a significant role in the physics of tBG even at intermediate twist angles and present a new pathway toward engineering band structure and symmetry-breaking phases in moire heterostructures.

Automated summary

Using ARPES, the effects of many-body interactions and displacement field on the band structure of twisted bilayer graphene (tBG) devices at an intermediate (3 degrees) twist angle are studied. The observed renormalization of bands at the K points suggests the influence of moire models of the Hartree-Fock interaction. Evidence of correlation-enhanced inversion symmetry-breaking, shown as tunable gaps at the Dirac points, suggests a new approach to engineering band structure and symmetry-breaking phases in moire heterostructures.