Effect of a magnetic field on the two-phonon Raman scattering in graphene

Clément Faugeras (1) , Piotr Kossacki (1, 2) , D. M. Basko (3) , Mario Amado (1) , Mike Sprinkle (4) , Claire Berger (5) , Walter A. de Heer (4) , Marek Potemski (1)

1 LNCMI-G - Laboratoire national des champs magnétiques intenses - Grenoble
2 IFD - Institute of Experimental Physics [Warsaw]
3 LPM2C - Laboratoire de physique et modélisation des milieux condensés
4 Georgia Institute of Technology [Atlanta]
5 NEEL - QuantECA - Circuits électroniques quantiques Alpes

We have studied, both experimentally and theoretically, the change of the so-called $2D$ band of the Raman scattering spectrum of graphene (the two-phonon peak near 2700~cm$^{-1}$) in an external magnetic field applied perpendicular to the graphene crystal plane at liquid helium temperature. A shift to lower frequency and broadening of this band is observed as the magnetic field is increased from 0 to 33~T. At fields up to 5--10~T the changes are quadratic in the field while they become linear at higher magnetic fields. This effect is explained by the curving of the quasiclassical trajectories of the photo-excited electrons and holes in the magnetic field, which enables us (i)~to extract the electron inelastic scattering rate, and (ii)~to conclude that electronic scattering accounts for about half of the measured width of the $2D$~peak.

Mots clés: Diffusion Raman; Graphene; Double résonance

Domaines: Systèmes mésoscopiques et effet Hall quantique [cond-mat.mes-hall]

Clément Faugeras, Piotr Kossacki, D. M. Basko, Mario Amado, Mike Sprinkle, et al.. Effect of a magnetic field on the two-phonon Raman scattering in graphene. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2010, 81 (15), pp.155436. ⟨10.1103/PhysRevB.81.155436⟩. ⟨hal-00445718⟩