2015/05/14 by Jian Huang, J. Huang, Jack Alexander-Webber +16
Engineering · Materials Science · Physics and Astronomy · #Condensed matter physics #Electron #Graphene #Graphene research and applications #Impurity #Low-power high-performance VLSI design #Materials science #Physics #Quantum and electron transport phenomena #Quantum mechanics #Scattering #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.92.075407
published as Phys. Rev. B 92, 075407 (2015) · 6 pages, 3 figures
arxiv created 2015/05/14 · openalex publication_date 2015/08/06 · arxiv updated 2015/08/07 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
We report a study of disorder effects on epitaxial graphene in the vicinity of the Dirac point by magnetotransport. 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\phantom\rule4.pt0exmeV, depending on the sample treatment. We investigate the scattering mechanisms and estimate the impurity density to be 3.0--9.1\ifmmode×\else\texttimes\fi1010\phantom\rule4pt0excm^\ensuremath-2 for our samples. A scattering asymmetry for electrons and holes is observed and is consistent with theoretical calculations for graphene on SiC substrates. We also show that the minimum conductivity increases with increasing disorder strength, in good agreement with quantum-mechanical numerical calculations.