Measurement of a filling-factor-dependent magnetophonon resonance in graphene using Raman-scattering spectroscopy
Y. Kim, J. M. Poumirol, A. Lombardo, N. G. Kalugin, T. Georgiou, Y. J. Kim, K. S. Novoselov, A. C. Ferrari, J. Kono, O. Kashuba, V. I. Fal’ko, and D. Smirnov
Accepted
We perform polarization-resolved Raman spectroscopy on graphene in magnetic fields up to 45T. This reveals a filling-factor-dependent, multi-component anti-crossing structure of the Raman $G$ peak, resulting from magneto-phonon resonances between magneto-excitons and circularly polarized $E_{2g}$ phonons. This structure is explained with a model of Raman scattering taking into account the effects of spatially inhomogeneous carrier densities and strain. This shows that random fluctuations of strain-induced pseudo-magnetic fields lead to increased scattering intensity inside the anti-crossing gap, consistent with the experiment.