title: Phase space for the breakdown of the quantum Hall effect in epitaxial graphene.
abstract: 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 30 T. At 2 K, breakdown currents (I(c)) almost 2 orders of magnitude greater than in GaAs devices are observed. The phase boundary of the dissipationless state (ρ(xx)=0) shows a [1-(T/T(c))2] dependence and persists up to T(c)>45  K at 29 T. With magnetic field I(c) was found to increase ∝B(3/2) and T(c)∝B2. As the Fermi energy pproaches the Dirac point, the ν=2 quantized Hall plateau appears continuously from fields as low as 1 T up to at least 19 T due to a strong magnetic field dependence of the carrier density.
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, United Kingdom.
authors.forename: J A
authors.initials: JA
authors.lastname: Alexander-Webber
authors.forename: A M R
authors.initials: AM
authors.lastname: Baker
authors.forename: T J B M
authors.initials: TJ
authors.lastname: Janssen
authors.forename: A
authors.initials: A
authors.lastname: Tzalenchuk
authors.forename: S
authors.initials: S
authors.lastname: Lara-Avila
authors.forename: S
authors.initials: S
authors.lastname: Kubatkin
authors.forename: R
authors.initials: R
authors.lastname: Yakimova
authors.forename: B A
authors.initials: BA
authors.lastname: Piot
authors.forename: D K
authors.initials: DK
authors.lastname: Maude
authors.forename: R J
authors.initials: RJ
authors.lastname: Nicholas