Renormalization of the Graphene Dispersion Velocity Determined from Scanning Tunneling Spectroscopy
Abstract
In graphene, as in most metals, electron-electron interactions renormalize the properties of electrons but leave them behaving like noninteracting quasiparticles. Many measurements probe the renormalized properties of electrons right at the Fermi energy. Uniquely for graphene, the accessibility of the electrons at the surface offers the opportunity to use scanned probe techniques to examine the effect of interactions at energies away from the Fermi energy, over a broad range of densities, and on a local scale. Using scanning tunneling spectroscopy, we show that electron interactions leave the graphene energy dispersion linear as a function of excitation energy for energies within +-200 meV of the Fermi energy. However, the measured dispersion velocity depends on density and increases strongly as the density approaches zero near the charge neutrality point, revealing a squeezing of the Dirac cone due to interactions.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 14, 2012
- Accession Number
- ADA569096
Entities
People
- Andrea Young
- Cory. R. Dean
- James C. Hone
- Jungseok Chae
- Kenji Watanabe
- Kenneth L. Shepard
- Lei Wang
- Suyong Jung
- Takashi Taniguchi
- Yuanda Gao
Organizations
- Columbia University