Cyclotron Resonance Study of Monolayer Graphene under Double Moiré Potentials
Momoko Onodera, Kei Kinoshita, Rai Moriya, Satoru Masubuchi, Kenji Watanabe, Takashi Taniguchi, Tomoki Machida
Abstract
We report the first cyclotron resonance study of monolayer graphene under double-moiré potentials in which the crystal axis of graphene is nearly aligned to those of both the top and bottom hexagonal boron nitride (h-BN) layers. Under mid-infrared light irradiation, we observe cyclotron resonance absorption with the following unique features: (1) cyclotron resonance magnetic field B CR is entirely different from that of nonaligned monolayer graphene, (2) B CR exhibits strong electron–hole asymmetry, and (3) splitting of B CR is observed for |ν| < 1, with the split maximum at |ν| = 1, resulting in eyeglass-shaped trajectories. These features are well explained by considering the large bandgap induced by the double moiré potentials, the electron–hole asymmetry in the Fermi velocity, and the Fermi-level-dependent enhancement of spin gaps, which suggests a large electron–electron correlation contribution in this system.