Phase-space for the breakdown of the quantum Hall effect in epitaxial graphene

J. A. Alexander-Webber, A. M. R. Baker, T. J. B. M. Janssen, A. Tzalenchuk, S. Lara-Avila, S. Kubatkin, R. Yakimova, B. A. Piot, D. K. Maude, R. J. Nicholas

Published 2013-04-17Version 1

We report the phase-space defined by the quantum Hall effect breakdown in polymer gated epitaxial graphene on SiC (SiC/G) as a function of temperature, current, carrier density, and magnetic fields up to 30T. At 2K breakdown currents ($I_c$) almost two orders of magnitude greater than in GaAs devices are observed. The phase boundary of the dissipationless state ($\rho_{xx}=0$) shows a (1-$(T/T_c)^2$) dependence and persists up to $T_c>45K$ at 29T. With magnetic field $I_c$ was found to increase $\propto B^{3/2}$ and $T_c \propto B^{1.88}$. As the Fermi energy approaches the Dirac point, the $\nu=2$ quantized Hall plateau appears continuously from fields as low as 1T up to at least 19T due to a strong magnetic field dependence of the carrier density.