Magnetically induced low density phases near the Dirac point

We demonstrated techniques for suspending graphene that isolate the charge carriers from substrate-induced potential fluctuations. The suspended samples provide access to the intrinsic properties of pristine graphene close to the Dirac point. Magneto-transport measurements on these samples show low temperature mobilities exceeding 200,000 cm$^{2}$/Vs for carrier densities below 5x10$^{9}$ cm$^{-2}$, values not attainable in semiconductors or non-suspended graphene$^{\ast }$. At sub-Kelvin temperatures and in magnetic fields up to 7T, we observed unconventional quantum Hall plateaus indicative of interaction effects. Near the Dirac point, coulomb blockade-like transmission was observed. $^{\ast }$\underline { }Xu Du, Anthony Barker, Ivan Skachko, and Eva Y. Andrei, \textit{Nature Nanotechnology}, Vol.3, 491, 2008