Details
| Originalsprache | Englisch |
|---|---|
| Aufsatznummer | 103045 |
| Fachzeitschrift | New Journal of Physics |
| Jahrgang | 14 |
| Publikationsstatus | Veröffentlicht - 29 Okt. 2012 |
Abstract
We have investigated the plasmon dispersion in quasi-free-standing monolayer graphene (QFMLG) and epitaxial monolayer graphene (MLG) layers by means of angle resolved electron energy loss spectroscopy. We have shown that various intrinsic p- and n-doping levels in QFMLG and MLG, respectively, do not lead to different overall slopes of the sheet plasmon dispersion, contrary to theoretical predictions. Only the coupling of the plasmon to single particle interband transitions becomes obvious in the plasmon dispersion by characteristic points of inflections, which coincide with the location of the Fermi level above or below the Dirac point. Further evidence is given by thermal treatment of the QFML graphene layer with gradual desorption of intercalated hydrogen, which shifts the chemical potential toward the Dirac point. From a detailed analysis of the plasmon dispersion, we deduce that the interaction strength between the plasmon and the electron-hole pair excitation is increased by about 30% in QFMLG compared to MLG, which is attributed to a modified dielectric environment of the graphene film.
ASJC Scopus Sachgebiete
- Physik und Astronomie (insg.)
- Allgemeine Physik und Astronomie
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in: New Journal of Physics, Jahrgang 14, 103045, 29.10.2012.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Manipulation of plasmon electron-hole coupling in quasi-free-standing epitaxial graphene layers
AU - Langer, Thomas
AU - Pfnür, Herbert
AU - Tegenkamp, Christoph
AU - Forti, Stiven
AU - Emtsev, Konstantin
AU - Starke, Ulrich
PY - 2012/10/29
Y1 - 2012/10/29
N2 - We have investigated the plasmon dispersion in quasi-free-standing monolayer graphene (QFMLG) and epitaxial monolayer graphene (MLG) layers by means of angle resolved electron energy loss spectroscopy. We have shown that various intrinsic p- and n-doping levels in QFMLG and MLG, respectively, do not lead to different overall slopes of the sheet plasmon dispersion, contrary to theoretical predictions. Only the coupling of the plasmon to single particle interband transitions becomes obvious in the plasmon dispersion by characteristic points of inflections, which coincide with the location of the Fermi level above or below the Dirac point. Further evidence is given by thermal treatment of the QFML graphene layer with gradual desorption of intercalated hydrogen, which shifts the chemical potential toward the Dirac point. From a detailed analysis of the plasmon dispersion, we deduce that the interaction strength between the plasmon and the electron-hole pair excitation is increased by about 30% in QFMLG compared to MLG, which is attributed to a modified dielectric environment of the graphene film.
AB - We have investigated the plasmon dispersion in quasi-free-standing monolayer graphene (QFMLG) and epitaxial monolayer graphene (MLG) layers by means of angle resolved electron energy loss spectroscopy. We have shown that various intrinsic p- and n-doping levels in QFMLG and MLG, respectively, do not lead to different overall slopes of the sheet plasmon dispersion, contrary to theoretical predictions. Only the coupling of the plasmon to single particle interband transitions becomes obvious in the plasmon dispersion by characteristic points of inflections, which coincide with the location of the Fermi level above or below the Dirac point. Further evidence is given by thermal treatment of the QFML graphene layer with gradual desorption of intercalated hydrogen, which shifts the chemical potential toward the Dirac point. From a detailed analysis of the plasmon dispersion, we deduce that the interaction strength between the plasmon and the electron-hole pair excitation is increased by about 30% in QFMLG compared to MLG, which is attributed to a modified dielectric environment of the graphene film.
UR - http://www.scopus.com/inward/record.url?scp=84869179622&partnerID=8YFLogxK
U2 - 10.1088/1367-2630/14/10/103045
DO - 10.1088/1367-2630/14/10/103045
M3 - Article
AN - SCOPUS:84869179622
VL - 14
JO - New Journal of Physics
JF - New Journal of Physics
SN - 1367-2630
M1 - 103045
ER -