Johannes Jobst, Daniel Waldmann, Igor V. Gornyi, Alexander D. Mirlin, Heiko B. Weber
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 (MR) is a manifestation of the electron-electron
interaction (EEI). We can consistently describe the data with a model for
diffusive (magneto)transport that also includes magnetic-field dependent
effects originating from ballistic time scales. We find an excellent agreement
between the experimentally observed temperature dependence of MR and the theory
of EEI in the diffusive regime. We can further assign a temperature-driven
crossover to the reduction of the multiplet modes contributing to EEI from 7 to
3 due to intervalley scattering. In addition, we find a temperature independent
ballistic contribution to the MR in classically strong magnetic fields.
View original:
http://arxiv.org/abs/1110.5893
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