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O: Fachverband Oberflächenphysik
O 62: [TT] Transport: Graphene 1 (jointly with MA, HL, DY, DS, O)
O 62.7: Talk
Thursday, March 29, 2012, 11:00–11:15, BH 334
Manifestation of electron-electron interaction in the magnetoresistance of graphene — •Johannes Jobst1, Daniel Waldmann1, Igor V. Gornyi2,3, Alexander D. Mirlin2,4,5, and Heiko B. Weber1 — 1Lehrstuhl für Angewandte Physik, Universität Erlangen-Nürnberg, Erlangen, Germany — 2Institut für Nanotechnologie, Karlsruhe Institute of Technology, Karlsruhe, Germany — 3A.F. Ioffe Physico-Technical Institute, St. Petersburg, Russia — 4Inst. für Theorie der kondensierten Materie, Karlsruhe Institute of Technology, Karlsruhe, Germany — 5Petersburg Nuclear Physics Institute, St. Petersburg, Russia
We investigate the magnetotransport in large area graphene Hall bars epitaxially grown on silicon carbide. In the intermediate field regime between weak localization and Landau quantization the observed temperature-dependent parabolic magnetoresistivity is a manifestation of electron-electron interaction. We can consistently describe the data with a model for diffusive (magneto)transport that covers the crossover to the ballistic regime. We find a temperature-driven crossover related to the reduction of the multiplet modes contributing to electron-electron interaction from 7 to 3 due to intervalley scattering. In addition we find a field-driven crossover from purely diffusive to partially ballistic behavior.