Physics of a disordered Dirac point in epitaxial graphene from temperature-dependent magnetotransport measurements

J Huang, J A Alexander-Webber, A M Baker, T J B M Janssen, Alexander Tzalenchuk, Vladimir Antonov, T Yager, S Lara-Avila, S Kubatkin, R Yakimova, R J Nicholas

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We report a study of disorder effects on epitaxial graphene in the vicinity of the Dirac point by magneto-transport. Hall effect measurements show that the carrier density increases quadratically with temperature, in good agreement with theoretical predictions which take into account intrinsic thermal excitation combined with electron-hole puddles induced by charged impurities. We deduce disorder strengths in the range 10.2 ~31.2 meV, depending on the sample treatment. We investigate the scattering mechanisms and estimate the impurity density to be 3.0 ~9.1 × 10^10 cm^−2 for our samples. An asymmetry in the electron/hole scattering is observed and is consistent with theoretical calculations for graphene on SiC substrates. We also show that the minimum conductivity increases with increasing disorder potential, in good agreement with quantum-mechanical numerical calculations.
Original languageEnglish
Article number075407
Pages (from-to)1-6
Number of pages6
JournalPhysical Review B
Issue number7
Early online date6 Aug 2015
Publication statusPublished - 15 Aug 2015


  • Electronic transport in graphene
  • Electronic structure of disordered solids
  • Theory of electronic transport; scattering mechanisms

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