[Zurück]

J. Sonntag, S. Reichardt, L Wirtz, B. Beschoten, M.I. Katsnelson, F. Libisch, C Stampfer:
"Impact of Many-Body Effects on Landau Levels in Graphene";
Poster: International Winterschool on Electronic Properties of Novel Materials (IWEPNM) 2018, Kichberg in Tirol; 17.04.2018 - 24.04.2018.

We present magneto-Raman spectroscopy measurements on suspended graphene to in-
vestigate the charge carrier density-dependent electron-electron interaction in the pres-
ence of Landau levels. Utilizing gate-tunable magneto-phonon resonances, we extract

the charge carrier density dependence of the Landau level transition energies and the
associated effective Fermi velocity vF . In contrast to the logarithmically divergence
of vF at zero magnetic field [1], we find a linear scaling of vF as a function of charge
carrier density, due to magnetic field-induced suppression of the long-range Coulomb

interaction. We quantitatively confirm our experimental findings by performing tight-
binding calculations on the level of the Hartree-Fock approximation [2]. We further

estimate that the involved transition energies are reduced by an exciton binding energy
of 6 meV [3].
1. G. Yu et al., Proc. Natl. Acad. Sci. U.S.A. 110, 3282 (2013).
2. L. Chizhova et al., Phys. Rev. B 92, 125411 (2015).
3. J. Sonntag et al., arXiv 1712.05648 (2017).