Quantum Hall Interferometry in Triangular Domains of Marginally Twisted Bilayer Graphene

Quantum Hall (QH) interferometry provides an archetypal platform for the experimental realization of braiding statistics of fractional QH states. However, the complexity of observing fractional statistics requires phase coherence over the length of the interferometer, as well as suppression of Coulomb charging energy. Here, we demonstrate a new type of QH interferometer based on marginally twisted bilayer graphene (mtBLG), with a twist angle theta approximate to 0.16 degrees. With the device operating in the QH regime, we observe distinct signatures of electronic Fabry-Perot and Aharonov-Bohm oscillations of the magneto-thermopower in the density-magnetic field phase space, at Landau level filling factors nu = 4, 8. We find that QH interference effects are intrinsic to the triangular AB/BA domains in mtBLG that show diminished Coulomb charging effects. Our results demonstrate phase-coherent interference of QH edge modes without any additional gate-defined complex architecture, which may be beneficial in experimental realizations of non-Abelian braiding statistics.

Automated summary

By utilizing marginally twisted bilayer graphene, a new type of Quantum Hall interferometer was demonstrated, showing distinct electronic Fabry-Perot and Aharonov-Bohm oscillations. Research findings suggest that interference effects are intrinsic to specific domains in the bilayer graphene, indicating diminished Coulomb charging effects.