Odd Integer Quantum Hall States with Interlayer Coherence in Twisted Bilayer Graphene.

ABSTRACT: We report on the quantum Hall effect in two stacked graphene layers rotated by 2°. The tunneling strength among the layers can be varied from very weak to strong via the mechanism of magnetic breakdown when tuning the density. Odd-integer quantum Hall physics is not anticipated in the regime of suppressed tunneling for balanced layer densities, yet it is observed. We interpret this as a signature of Coulomb interaction induced interlayer coherence and Bose-Einstein condensation of excitons that form at half filling of each layer. A density imbalance gives rise to reentrant behavior due to a phase transition from the interlayer coherent state to incompressible behavior caused by simultaneous condensation of both layers in different quantum Hall states. With increasing overall density, magne

SUBMITTER: Kim Y 

PROVIDER: S-EPMC8289309 | biostudies-literature | 2021 May

REPOSITORIES: biostudies-literature