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

Phys. Rev. Lett. 110, 227402 – Published 29 May 2013

Abstract

We perform polarization-resolved Raman spectroscopy on graphene in magnetic fields up to 45 T. This reveals a filling-factor-dependent, multicomponent anticrossing structure of the Raman $G$ peak, resulting from magnetophonon resonances between magnetoexcitons and $E_{2 g}$ 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 pseudomagnetic fields lead to increased scattering intensity inside the anticrossing gap, consistent with the experiments.

Received 23 November 2012

DOI:https://doi.org/10.1103/PhysRevLett.110.227402

Authors & Affiliations

Y. Kim¹, J. M. Poumirol¹, A. Lombardo², N. G. Kalugin³, T. Georgiou⁴, Y. J. Kim⁴, K. S. Novoselov⁴, A. C. Ferrari², J. Kono⁵, O. Kashuba⁶, V. I. Fal’ko^7,8, and D. Smirnov^1,*

¹National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
²Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, United Kingdom
³Department of Materials and Metallurgical Engineering, New Mexico Tech, Socorro, New Mexico 87801, USA
⁴School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
⁵Department of Electrical and Computer Engineering and Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
⁶Institute for Theoretical Physics A, RWTH Aachen, D-52074 Aachen, Germany
⁷Department of Physics, Lancaster University, Lancaster, LA1 4YB, United Kingdom
⁸DPMC, Université de Genève, CH-1211 Genève 4, Switzerland