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Updated: Apr 24, 2026

High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
Published on: June 28, 2016
Optical-phonon resonances with saddle-point excitons in twisted-bilayer graphene
Ado Jorio1, Mark Kasperczyk, Nick Clark
1Photonics Laboratory, ETH Zürich , 8093 Zürich, Switzerland.
Abstract:
Twisted-bilayer graphene (tBLG) exhibits van Hove singularities in the density of states that can be tuned by changing the twisting angle θ. A θ-defined tBLG has been produced and characterized with optical reflectivity and resonance Raman scattering. The θ-engineered optical response is shown to be consistent with persistent saddle-point excitons. Separate resonances with Stokes and anti-Stokes Raman scattering components can be achieved due to the sharpness of the two-dimensional saddle-point excitons, similar to what has been previously observed for one-dimensional carbon nanotubes. The excitation power dependence for the Stokes and anti-Stokes emissions indicate that the two processes are correlated and that they share the same phonon.
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