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arXiv · 2007.08036

Many-body effects in suspended graphene probed through magneto-phonon resonances

Stéphane Berciaud·Marek Potemski·Clément Faugeras
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Abstract

We make use of micro-magneto Raman scattering spectroscopy to probe magneto-phonon resonances (MPR) in suspended mono- to penta-layer graphene. MPR correspond to avoided crossings between zone-center optical phonons (G-mode) and optically-active inter Landau level (LL) transitions and provide a tool to perform LL spectroscopy at a fixed energy ($\approx 197~\rm{meV}$) set by the G-mode phonon. Using a single-particle effective bilayer model, we readily extract the velocity parameter associated with each MPR. A single velocity parameter slightly above the bulk graphite value suffices to fit all MPR for $N\geq2$ layer systems. In contrast, in monolayer graphene, we find that the velocity parameter increases significantly from $(1.23\pm 0.01) \times 10^6~\mathrm{m.s^{-1}}$ up to $(1.45\pm0.02) \times 10^6~\mathrm{m.s^{-1}}$ as the first to third optically-active inter LL transition couple to the G-mode phonon. This result is understood as a signature of enhanced many-body effects in unscreened graphene.

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Stéphane Berciaud, Marek Potemski, Clément Faugeras. 2020-07-15. Many-body effects in suspended graphene probed through magneto-phonon resonances. https://doi.org/10.1002/pssr.202000345

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