RSS icon
Twitter icon
Facebook icon
Vimeo icon
YouTube icon

Charged-impurity scattering in graphene

TitleCharged-impurity scattering in graphene
Publication TypeJournal Article
Year of Publication2008
AuthorsJ. H. Chen, C. Jang, S. Adam, M. S. Fuhrer, E. D. Williams, and M. Ishigami
JournalNat. Phys.
Volume4
Pagination377–381
Date Publishedapr
ISSN1745-2473
Keywords2008, No Fellows
Abstract

Since the initial demonstration of the ability to experimentally isolate a single graphene sheet1, a great deal of theoretical work has focused on explaining graphene's unusual carrier-density-dependent conductivity (n), and its minimum value (min) of nearly twice the quantum unit of conductance (4e2/h) (refs 1, 2, 3, 4, 5, 6). Potential explanations for such behaviour include short-range disorder7, 8, 9, 10, 'ripples' in graphene's atomic structure11, 12 and the presence of charged impurities7, 8, 13, 14, 15, 16, 17, 18. Here, we conduct a systematic study of the last of these mechanisms, by monitoring changes in electronic characteristics of initially clean graphene19 as the density of charged impurities (nimp) is increased by depositing potassium atoms onto its surface in ultrahigh vacuum. At non-zero carrier density, charged-impurity scattering produces the widely observed linear dependence1, 2, 3, 4, 5, 6 of (n). More significantly, we find that min occurs not at the carrier density that neutralizes nimp, but rather the carrier density at which the average impurity potential is zero15. As nimp increases, min initially falls to a minimum value near 4e2/h. This indicates that min in the present experimental samples1, 2, 3, 4, 5, 6 is governed not by the physics of the Dirac point singularity20, 21, but rather by carrier-density inhomogeneities induced by the potential of charged impurities6, 8, 14, 15.

URLhttp://dx.doi.org/10.1038/nphys935

Subscribe to A Quantum Bit 

Quantum physics began with revolutionary discoveries in the early twentieth century and continues to be central in today’s physics research. Learn about quantum physics, bit by bit. From definitions to the latest research, this is your portal. Subscribe to receive regular emails from the quantum world. Previous Issues...

Sign Up Now

Sign up to receive A Quantum Bit in your email!

 Have an idea for A Quantum Bit? Submit your suggestions to jqi-comm@umd.edu