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

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...

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Bibliographic Details
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:
Online Access:https://hdl.handle.net/10356/99687
http://hdl.handle.net/10220/9186
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Institution: Nanyang Technological University
Language: English
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Summary: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.