F. Amet, J. R. Williams, K. Watanabe, T. Taniguchi, D. Goldhaber-Gordon
The fate of the low-temperature conductance at the charge-neutrality (Dirac) point in a single sheet of graphene is investigated down to 20 mK. The potential fluctuations in graphene are made artificially small by using a dual top- and back-gate geometry such that screening reduces the intrinsic disorder potential. As the temperature is lowered, the peak resistivity diverges with a power-law behavior and becomes as high as several Megaohms per square at the lowest temperature, in contrast with the commonly observed saturation of the conductivity. As a transverse magnetic field is applied, our device remains insulating and directly transitions to the {\nu}=0 quantum Hall state at a field of 100 mT.
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http://arxiv.org/abs/1209.6364
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