Plateau–insulator transition in graphene

We investigate the quantum Hall effect (QHE) in a graphene sample with Hall-bar geometry close to the Dirac point at high magnetic fields up to 28 T. We have discovered a plateau–insulator quantum phase transition passing from the last plateau for the integer QHE in graphene to an insulator regime ν=−2→ν=0. The analysis of the temperature dependence of the longitudinal resistance gives a value for the critical exponent associated with the transition equal to κ=0.58±0.03