Probing moir\'{e} physics in low angle twisted bilayer graphene

When two sheets of honeycomb structured graphene are stacked together, a moir\'{e} pattern that depend on the twist angle forms. A gapped superlattice band structure is resulted when this angle is small enough so that the energy of moir\'{e} modulated hybridization between wave functions on the two sheets that are separated by only 0.34nm is low enough. Apart from the energy gaps, the superlattice band structure also manifests reduced Fermi velocity which implies comparatively higher density of states, multiple van Hove singularities below and above the gaps, and Hofstadter butterfly physics when magnetic field is applied. We show electronic transport measurements of high-quality low-angle twist bilayer graphene devices fabricated by a novel tear-and-stack technique, at zero, low and high magnetic fields. We also present angle dependence of the electronic structure along with magneto-transport features that possibly imply electron-electron interactions. A brief discussion about the transition between the low-twist and high-twist bilayer graphene, the physics of the latter of which is believed to be essentially based on decoupled monolayer graphene according to our previous work, is included.