Mechanism of the far-infrared absorption of carbon-nanotube films

The far-infrared conductivity of single-wall carbon-nanotube ensembles is dominated by a broad absorption peak around 4 THz whose origin is still debated. We observe an overall depletion of this peak when the nanotubes are excited by a short visible laser pulse. This finding excludes optical absorpt...

Full description

Saved in:
Bibliographic Details
Published inPhysical review letters Vol. 101; no. 26; p. 267403
Main Authors Kampfrath, T, von Volkmann, K, Aguirre, C M, Desjardins, P, Martel, R, Krenz, M, Frischkorn, C, Wolf, M, Perfetti, L
Format Journal Article
LanguageEnglish
Published United States 31.12.2008
Online AccessGet more information

Cover

More Information
Summary:The far-infrared conductivity of single-wall carbon-nanotube ensembles is dominated by a broad absorption peak around 4 THz whose origin is still debated. We observe an overall depletion of this peak when the nanotubes are excited by a short visible laser pulse. This finding excludes optical absorption due to a particle-plasmon resonance and instead shows that interband transitions in tubes with an energy gap of approximately 10 meV dominate the far-infrared conductivity. A simple model based on an ensemble of two-level systems naturally explains the weak temperature dependence of the far-infrared conductivity by the tube-to-tube variation of the chemical potential.
ISSN:0031-9007
DOI:10.1103/physrevlett.101.267403