Zone folding effect in Raman G-band intensity of twisted bilayer graphene

• Main Authors: Dresselhaus, Mildred S., Sato, Kentaro, Saito, Riichiro, Cong, Chunxiao, Yu, Ting
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2013
• Subjects: DRNTU::Science::Physics::Atomic physics
• Online Access: https://hdl.handle.net/10356/99687; http://hdl.handle.net/10220/9186
• Institution: Nanyang Technological University

The G-band Raman intensity is calculated for twisted bilayer graphene as a function of laser excitation energy based on the extended tight binding method. Here we explicitly consider the electron-photon and electron-phonon matrix elements of twisted bilayer graphene to calculate the resonance Raman intensity. The G-band Raman intensity is sensitive to the laser excitation energy and the twisting angle between the layers as a result of folding the electronic energy band structure. The Van Hove energy singularity, which is an electron transition energy between the conduction and valence bands, depends on n−m of the twisting vector (n,m). The relative intensity of the G band as a function of twisting vectors is presented, which should be useful for the experimental identification of the twisting angle.