Influences of Mechanical Deformation on Bilayer Graphene's Magneto-Optical Absorption Properties

Abstract

The low-frequency magneto-optical absorption properties of bilayer Bernal graphene under uniaxial stress are investigated by using the gradient approximation. The magnetic field effectively condenses the electron states into discrete Landau levels, and the optical absorption spectra exhibit prominent peaks structures. There exists an optical selection rule for undeformed bilayer Bernal graphene due to the spatial symmetry of the electron wave functions. The stress distorts the wave functions, and destroys their spatial symmetry. The disruption of the spatial symmetry depends not only on the magnitude but also the direction of the strain. Therefore, the optical selection rule in bilayer Bernal graphene can be controlled by mechanical deformation. Many optical transitions violating the selection rule are allowed at sufficiently large strain. The variations of the absorption peak energies with the strain and the magnetic field strength are also explored. These theoretical predictions can be validated by opti...