Eur. Phys. J. B 42, 345-350 (2004)
https://doi.org/10.1140/epjb/e2004-00389-0

Interaction between concentric tubes in DWCNTs

¹ Institut für Materialphysik, Universität Wien, Strudlhofgasse 4, 1090 Wien, Austria
² Leibniz Institute of Solid State and Materials Research Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany
³ Faculty of Physics, University of Sofia, Sofia, Bulgaria
⁴ AIST, Central 4, Higashi 1-1-1, Tsukuba, 305-8562 Ibaraki, Japan

Corresponding author: ^a rpfei@ap.univie.ac.at

Received: 14 June 2004
Revised: 15 September 2004
Published online: 23 December 2004

Abstract

A detailed investigation of the Raman response of the inner tube radial breathing modes (RBMs) in double-wall carbon nanotubes is reported. It revealed that the number of observed RBMs is two to three times larger than the number of possible tubes in the studied frequency range. This unexpected increase in Raman lines is attributed to a splitting of the inner tube response. It originates from the possibility that one type of inner tubes may form in different types of outer tubes. In this case, a splitting of lines results since the inner tube RBM frequency depends on the diameter of the outer tube. Finally, a comparison of the inner tube RBMs and the RBMs of tubes in bundles gave clear evidence for a stronger interaction between tubes in a bundle as compared to the interaction between inner and outer tubes.