Physics of a disordered Dirac point in epitaxial graphene from temperature-dependent magnetotransport measurements
Journal article, 2015
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 meV, depending on the sample treatment. We investigate the scattering mechanisms and estimate the impurity density to be 3.0-9.1x10(10) cm(-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.
Physics
transport
scattering
boron-nitride
Author
J. Huang
University of Oxford
J. A. Alexander-Webber
University of Oxford
A. M. R. Baker
University of Oxford
Tjbm Janssen
National Physical Laboratory
A.Y. Tzalenchuk
Royal Holloway University of London
National Physical Laboratory
V. Antonov
Royal Holloway University of London
Thomas Yager
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Samuel Lara Avila
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Sergey Kubatkin
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
R. Yakimova
Linkopings universitet
R. J. Nicholas
University of Oxford
Physical Review B - Condensed Matter and Materials Physics
1098-0121 (ISSN)
Vol. 92 7 075407Graphene-Based Revolutions in ICT And Beyond (Graphene Flagship)
European Commission (FP7) (EC/FP7/604391), 2013-10-01 -- 2016-03-31.
Areas of Advance
Nanoscience and Nanotechnology
Subject Categories (SSIF 2011)
Condensed Matter Physics
DOI
10.1103/PhysRevB.92.075407