Image mini-twisted-angle bilayer graphene by magneto scanning near-field optical microscopy

The application of magneto scanning near-field optical microscopy (m-SNOM) has yielded critical insights into the excitation of Dirac magnetoexcitons (DiME) on monolayer graphene, contingent upon the photon energy matching the Landau level at magnetic field [1]. The emergence of a moiré superlattice, a consequence of the angular overlap of two graphene layers, alters the electronic and plasmonic properties. In this talk, we image a twist bilayer graphene (TBG) with a mini twist angle (~0.5 degrees) with magnetic fields up to 7 Tesla. As the moiré superlattice matches the magnetic length, it exerts a profound modulation of DiME and the magneto nano-photocurrent.