We report transport measurements through graphene on SrTiO3 substrates as a function of magnetic field B, carrier density n, and temperature T. The large dielectric constant of SrTiO3 screens very effectively long-range electron-electron interactions and potential fluctuations, making Dirac electrons in graphene virtually non-interacting. The absence of interactions results in a unexpected behavior of the longitudinal resistance in the N=0 Landau level, and in a large suppression of the transport gap in nano-ribbons. The "bulk" transport properties of graphene at B=0T, on the contrary, are completely unaffected by the substrate dielectric constant.
@article{arxiv.1107.3241,
title = {Transport through graphene on SrTiO3},
author = {N. J. G. Couto and B. Sacepe and A. F. Morpurgo},
journal= {arXiv preprint arXiv:1107.3241},
year = {2011}
}