Optical transitions at commensurate angles in a misoriented bilayer graphene in an external magnetic field

Misoriented bilayer graphene with commensurate angles shows unique magneto-optical properties. The optical absorption spectra of such a system strongly depend on the angle of rotation. For a general commensurate twist angle, the absorption spectra has a simple single-peak structure. However, our studies indicate that there are special angles at which the absorption spectra of the rotated bilayer exhibit well developed multipeak structures. These angles correspond to even symmetry of the rotated graphene with respect to the sublattice exchange. Magnetospectroscopy can therefore be a potentially useful scheme to determine the twist angles.