Uniform peak optical conductivity in single-walled carbon nanotubes
Recent Rayleigh scattering measurements show that all single-walled carbon nanotubes have a peak optical conductivity of approximately 8 e²/h, independent of radius, chiral angle, or whether the nanotube is semiconducting or metallic [D. Y. Joh et al., Nat. Nanotechnol. 6, 51 (2011)]. We show that this uniform peak conductivity is a consequence of the relativistic band structure and strength of the Coulomb interaction in carbon nanotubes. We also show that a simple exciton model accurately describes the general phenomenology and the numerical value of the peak optical conductivity. Our work illustrates the need for careful treatment of relaxation mechanisms in modeling the optoelectronic properties of carbon nanotubes.
© 2011 American Physical Society. Received 2 February 2011; revised manuscript received 12 May 2011; published 12 September 2011. J.M.K.would like to thank D. Joh and L. Hermann for many helpful discussions of the experiment. This work was funded by the Cornell Center for Materials Research, the Center for Molecular Interfacing, the NSF CAREER grant, the Air Force Office of Scientific Research (NE and IO), the Camille and Henry Dreyfus Foundation, the David and Lucile Packard Foundation, and the Alfred P. Sloan Foundation.
Accepted Version - 1101.3546.pdf
Published - PhysRevB.84.125428.pdf