Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 81: Graphene: Transport incl. Spin Physics and Magnetic Fields I

HL 81.6: Talk

Thursday, March 29, 2012, 16:15–16:30, ER 270

Polarization resolved magneto-Raman scattering of graphene on natural graphite — •Matthias Kühne^1,2, Clément Faugeras², Piotr Kossacki^2,3, Aurélien L. L. Nicolet², Milan Orlita^2,4, Yu. I. Latyshev⁵, and Marek Potemski² — ¹Karlsruher Institut für Technologie, Physikalisches Institut, 76131 Karlsruhe — ²LNCMI-CNRS (UJF, UPS, INSA), 38042 Grenoble, France — ³Institute of Experimental Physics, University of Warsaw, 00-681 Warsaw, Poland — ⁴Institute of Physics, Charles University, 121 16 Praha 2, Czech Republic — ⁵Institute of Radio Engineering and Electronics, RAS, 125009, Moscow, Russia

It was recently demonstrated that purely electronic Raman scattering can be measured in graphene flakes on bulk natural graphite subject to a quantizing magnetic field [1]. We investigate a similar graphene flake by micro-Raman scattering at 4.2K and in magnetic fields up to 29T. Different types of electronic excitations are observed and identified in circular polarization resolved experiments. The magnetic field evolution of these excitations reveals details of the graphene band structure, such as the electron-hole asymmetry, as well as possible signs of an interaction with the underlying substrate. The latter is further suggested by an unusually rich coupling between the zone-center E_2g-phonon and the electronic excitations.

[1] C. Faugeras et al., Phys. Rev. Lett. 107, 036807 (2011)