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@ARTICLE{Sonntag:1025618,
author = {Sonntag, J. and Watanabe, K. and Taniguchi, T. and
Beschoten, B. and Stampfer, C.},
title = {{C}harge carrier density dependent {R}aman spectra of
graphene encapsulated in hexagonal boron nitride},
journal = {Physical review / B},
volume = {107},
number = {7},
issn = {2469-9950},
address = {Woodbury, NY},
publisher = {Inst.},
reportid = {FZJ-2024-03007},
pages = {075420},
year = {2023},
abstract = {We present low-temperature Raman measurements on
gate-tunable graphene encapsulated in hexagonal boron
nitride, which allows us to study in detail the Raman G and
2D mode frequencies and linewidths as a function of the
charge carrier density. We observe a clear softening of the
Raman G mode (of up to 2.5 cm−1) at low carrier density
due to the phonon anomaly and a residual G mode linewidth of
≈3.5cm−1 at high doping. By analyzing the G mode
dependence on doping and laser power we extract an
electron-phonon-coupling constant of ≈4.4×10−3 (for the
G mode phonon). The ultraflat nature of encapsulated
graphene results in a minimum Raman 2D peak linewidth of
14.5 cm−1 and allows us to observe intrinsic
electron-electron scattering-induced broadening of the 2D
peak of up to 18 cm−1 for an electron density of
5×1012cm−2 (laser excitation energy of 2.33 eV). Our
findings not only provide insights into electron-phonon
coupling and the role of electron-electron scattering in the
broadening of the 2D peak but also crucially show the
limitations when it comes to the use of Raman spectroscopy
(i.e., the use of the frequencies and the linewidths of the
G and 2D modes) to benchmark graphene in terms of charge
carrier density, strain, and strain inhomogeneities. This is
particularly relevant when utilizing spatially resolved 2D
Raman linewidth maps to assess substrate-induced
nanometer-scale strain variations.},
cin = {PGI-9 / PGI-11},
ddc = {530},
cid = {I:(DE-Juel1)PGI-9-20110106 / I:(DE-Juel1)PGI-11-20170113},
pnm = {5221 - Advanced Solid-State Qubits and Qubit Systems
(POF4-522) / 5222 - Exploratory Qubits (POF4-522) /
GrapheneCore3 - Graphene Flagship Core Project 3 (881603) /
2D4QT - 2D Materials for Quantum Technology (820254) / DFG
project 437214324 - Durchstimmbare Twistronics: Lokales
Tuning und lokale Detektion topologischer Randzustände und
Supraleitung in Zweilagigen-Graphen (437214324) / DFG
project 436607160 - NEMS Sensoren aus
2D-Material-Heterostrukturen (436607160) / DFG project
390534769 - EXC 2004: Materie und Licht für
Quanteninformation (ML4Q) (390534769)},
pid = {G:(DE-HGF)POF4-5221 / G:(DE-HGF)POF4-5222 /
G:(EU-Grant)881603 / G:(EU-Grant)820254 /
G:(GEPRIS)437214324 / G:(GEPRIS)436607160 /
G:(GEPRIS)390534769},
typ = {PUB:(DE-HGF)16},
UT = {WOS:000933970900003},
doi = {10.1103/PhysRevB.107.075420},
url = {https://juser.fz-juelich.de/record/1025618},
}