Theory of thermopower in twodimensional graphene
Abstract
Motivated by recent experiments by Yuri M. Zuev [Phys. Rev. Lett. 102, 096807 (2009)], Peng Wei [Phys. Rev. Lett. 102, 166808 (2009)], and Joseph G. Checkelsky [Phys. Rev. B 80, 081413(R) (2009)], we calculate the thermopower of graphene incorporating the energy dependence of various transport scattering times. We find that scattering by screened charged impurities gives a reasonable explanation for the measured thermopower. The calculated thermopower behaves as 1/n at high densities, but saturates at low densities. We also find that the thermopower scales with the normalized temperature T/T_{F} and does not depend on the impurity densities, but strongly depends on the finestructure constant r_{s} and on the location of the impurities. We discuss the deviation from the Mott formula in graphene thermopower and use an effectivemedium theory to calculate thermopower at low carrier density regimes where electronhole puddles dominate.
 Publication:

Physical Review B
 Pub Date:
 December 2009
 DOI:
 10.1103/PhysRevB.80.235415
 arXiv:
 arXiv:0902.1749
 Bibcode:
 2009PhRvB..80w5415H
 Keywords:

 73.50.h;
 81.05.Uw;
 72.10.d;
 72.15.Jf;
 Electronic transport phenomena in thin films;
 Carbon diamond graphite;
 Theory of electronic transport;
 scattering mechanisms;
 Thermoelectric and thermomagnetic effects;
 Condensed Matter  Mesoscale and Nanoscale Physics;
 Condensed Matter  Disordered Systems and Neural Networks
 EPrint:
 5 pages, 3 figures