Transconductance fluctuations as a probe for interaction induced quantum   Hall states in graphene
  Transport measurements normally provide a macroscopic, averaged view of the sample, so that disorder prevents the observation of fragile interaction induced states. Here, we demonstrate that transconductance fluctuations in a graphene field effect transistor reflect charge localization phenomena on the nanometer scale due to the formation of a dot network which forms near incompressible quantum states. These fluctuations give access to fragile broken-symmetry and fractional quantum Hall states even though these states remain hidden in conventional magnetotransport quantities. 
Dong Su Lee, Viera Skakalova, R. Thomas Weitz, Klaus von Klitzing, and   Jurgen H. Smet
cond-mat.mes-hall