Measurement of Filling-Factor-Dependent Magnetophonon Resonances in Graphene Using Raman Spectroscopy

TL;DR

This study uses high-field Raman spectroscopy to investigate how magnetophonon resonances in graphene depend on filling factors, revealing complex anticrossing structures influenced by inhomogeneous strain and carrier density variations.

Contribution

It introduces a model accounting for spatial inhomogeneities to explain filling-factor-dependent magnetophonon resonances observed in graphene.

Findings

Observation of multi-component anticrossing structures in Raman spectra.

Correlation between strain-induced pseudo-magnetic fields and scattering intensity.

Validation of the model with experimental data.

Abstract

We perform polarization-resolved Raman spectroscopy on graphene in magnetic fields up to 45T. This reveals a filling-factor-dependent, multi-component anticrossing structure of the Raman G peak, resulting from magnetophonon resonances between magnetoexcitons and E$_{2g}$ phonons. This is explained with a model of Raman scattering taking into account the effects of spatially inhomogeneous carrier densities and strain. Random fluctuations of strain-induced pseudo-magnetic fields lead to increased scattering intensity inside the anti-crossing gap, consistent with the experiment.