First-principles Study on Tuning Electronic and Optical Properties in Graphene Rotation on H-Bn

Graphene rotation on hexagonal boron nitride(h-BN) is of great significance in fundamental research and device exploration for its unique energy band structure, rich physical and chemical properties. Twisting angle technique of Graphene/h-BN heterojunction(G/h-BN) is considered as effective approach for modulating band and opto-electronic properties. In this work, G/h-BN heterojunction with different twist angles are discussed based on density functional theory and a critical angle of similar to 13.17 degrees is found which tends to rotate towards 21.79 degrees or 7.34 degrees. Band gap at the primary Dirac point is opened by 44 meV, and it changes from 0.7 meV to 7.1 meV when the rotation angle is twisted from 21.79 degrees to 7.34 degrees, which is related to the motion properties of carriers in different directions. Meanwhile, the optical properties of the twisting G/h-BN are very sensitive to the atom bonding. The calculated electron-photon interactions show that reflectivity and energy loss function have significant changes at different twist angles, indicates that the twisting angle can tuning the optical absorption spectrum and reflectivity.