Optical transitions between Landau levels: AA-stacked bilayer graphene

The magneto-optical absorption spectra of AA-stacked bilayer graphene (AABG) exhibit two kinds of absorption peaks resulting from two groups of Landau levels (LLs). Only intragroup excitations that follow a single selection rule take place. The excitation channels are altered as the field strength approaches a critical strength. These optical properties can be comprehended by the characteristics of the LL wave functions. A comparison of AABG and AB-stacked bilayer graphene (BBG) demonstrates that the optical properties are dominated by the stacking symmetry. The presented results could offer a way to distinguish AABG from BBG and monolayer graphene. (C) 2010 American Institute of Physics. [doi:10.1063/1.3488806]