Optical-Phonon Resonances with Saddle-Point Excitons in Twisted-Bilayer Graphene

Ado Jorio; Mark Kasperczyk; Nick Clark; Elke Neu; Patrick Maletinsky; Aravind Vijayaraghavan; Lukas Novotny

doi:10.1021/nl502412g

Optical-Phonon Resonances with Saddle-Point Excitons in Twisted-Bilayer Graphene

Ado Jorio, Mark Kasperczyk, Nick Clark, Elke Neu, Patrick Maletinsky, Aravind Vijayaraghavan, Lukas Novotny

Research output: Contribution to journal › Article › peer-review

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.

Original language	English
Pages (from-to)	5687-5692
Number of pages	6
Journal	Nano Letters
Volume	14
Issue number	10
DOIs	https://doi.org/10.1021/nl502412g
Publication status	Published - 2014

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title = "Optical-Phonon Resonances with Saddle-Point Excitons in Twisted-Bilayer Graphene",

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.",

author = "Ado Jorio and Mark Kasperczyk and Nick Clark and Elke Neu and Patrick Maletinsky and Aravind Vijayaraghavan and Lukas Novotny",

year = "2014",

doi = "10.1021/nl502412g",

language = "English",

volume = "14",

pages = "5687--5692",

journal = "Nano Letters",

issn = "1530-6984",

publisher = "American Chemical Society",

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TY - JOUR

T1 - Optical-Phonon Resonances with Saddle-Point Excitons in Twisted-Bilayer Graphene

AU - Jorio, Ado

AU - Kasperczyk, Mark

AU - Clark, Nick

AU - Neu, Elke

AU - Maletinsky, Patrick

AU - Vijayaraghavan, Aravind

AU - Novotny, Lukas

PY - 2014

Y1 - 2014

N2 - 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.

AB - 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.

U2 - 10.1021/nl502412g

DO - 10.1021/nl502412g

M3 - Article

SN - 1530-6984

VL - 14

SP - 5687

EP - 5692

JO - Nano Letters

JF - Nano Letters

IS - 10

ER -

Optical-Phonon Resonances with Saddle-Point Excitons in Twisted-Bilayer Graphene

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