Title | Measurement of the optical conductivity of graphene. |
Publication Type | Journal Article |
Year of Publication | 2008 |
Authors | Mak, KFai, Sfeir, MY, Wu, Y, Lui, CHung, Misewich, JA, Heinz, TF |
Journal | Phys Rev Lett |
Volume | 101 |
Issue | 19 |
Pagination | 196405 |
Date Published | 2008 Nov 07 |
ISSN | 0031-9007 |
Abstract | Optical reflectivity and transmission measurements over photon energies between 0.2 and 1.2 eV were performed on single-crystal graphene samples on a SiO2 substrate. For photon energies above 0.5 eV, graphene yielded a spectrally flat optical absorbance of (2.3+/-0.2)%. This result is in agreement with a constant absorbance of pialpha, or a sheet conductivity of pie2/2h, predicted within a model of noninteracting massless Dirac fermions. This simple result breaks down at lower photon energies, where both spectral and sample-to-sample variations were observed. This "nonuniversal" behavior is explained by including the effects of doping and finite temperature, as well as contributions from intraband transitions. |
DOI | 10.1103/PhysRevLett.101.196405 |
Alternate Journal | Phys. Rev. Lett. |
PubMed ID | 19113291 |