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arXiv · 1712.05648

Impact of Many-Body Effects on Landau Levels in Graphene

J. Sonntag·S. Reichardt·L. Wirtz·B. Beschoten·M. I. Katsnelson·F. Libisch·C. Stampfer
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Abstract

We present magneto-Raman spectroscopy measurements on suspended graphene to investigate the charge carrier density-dependent electron-electron interaction in the presence 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 $v_\mathrm{F}$. In contrast to the logarithmic divergence of $v_\mathrm{F}$ at zero magnetic field, we find a piecewise linear scaling of $v_\mathrm{F}$ as a function of charge carrier density, due to a 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, which also allow us to estimate an excitonic binding energy of $\approx$ 6 meV contained in the experimentally extracted Landau level transitions energies.

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J. Sonntag, S. Reichardt, L. Wirtz, B. Beschoten, M. I. Katsnelson, F. Libisch, C. Stampfer. 2017-12-15. Impact of Many-Body Effects on Landau Levels in Graphene. https://doi.org/10.1103/physrevlett.120.187701

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