title: Phonon trigonal warping effect in graphite and carbon nanotubes.
abstract: The one-dimensional structure of carbon nanotubes leads to quantum confinement of the wave vectors for the electronic states, thus making the double resonance Raman process selective, not only of the magnitude, but also of the direction of the phonon wave vectors. This additional selectivity allows us to reconstruct the phonon dispersion relations of 2D graphite, by probing individual single wall carbon nanotubes of different chiralities by resonance Raman spectroscopy, and using different laser excitation energies. In particular, we are able to measure the anisotropy, or the trigonal warping effect, in the phonon dispersion relations around the hexagonal corner of the Brillouin zone of graphite.
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307, USA.
authors.forename: Ge G
authors.initials: GG
authors.lastname: Samsonidze
authors.forename: R
authors.initials: R
authors.lastname: Saito
authors.forename: A
authors.initials: A
authors.lastname: Jorio
authors.forename: A G
authors.initials: AG
authors.lastname: Souza Filho
authors.forename: A
authors.initials: A
authors.lastname: Grüneis
authors.forename: M A
authors.initials: MA
authors.lastname: Pimenta
authors.forename: G
authors.initials: G
authors.lastname: Dresselhaus
authors.forename: M S
authors.initials: MS
authors.lastname: Dresselhaus