文档介绍：Effect of Point Defects on Phonon-Mediated Thermal Transport
in Carbon Nanotubes
Arun Bodapati,1 Patrick K. Schelling,2 and Pawel Keblinski1, ∗
1Department of Materials Science and Engineering,
Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
2Advanced Materials Processing and Analysis Center (AMPAC),
Department of Physics,
University of Central Florida, Orlando, FL 32816, USA.
Abstract
We analyze the vibrational modes of chemically-functionalized single-walled carbon nanotubes
within the harmonic approximation to examine the effect of point defects on phonons. We find that
the majority of the vibrational modes in functionalized tubes are delocalized but not polarized.
Only low-frequency, long-wavelength phonons preserve their polarization in the presence of high
defect densities. Molecular-dynamics simulations demonstrate that low-frequency acoustic phonons
exhibit weak scattering from point defects.
∗Electronic address: ******@
1
I. INTRODUCTION
One of the remarkable properties of carbon nanotubes is their very high thermal conduc-
tivity that puted first from molecular simulations [1] and later measured in experi-
ment [2]. The first molecular-dynamics (MD) simulation of single-walled carbon nanotubes
(Ts) yielded a thermal conductivity as high as 6000 W/m-K. Later simulations, using
either different simulation techniques or empirical potentials, reported somewhat lower val-
ues [3, 4]. Subsequent molecular simulations [4] and theoretical considerations [5, 6] demon-
strated that the thermal conductivity of individual Ts can exhibit strong length de-
pendence due to ballistic propagation of long-wavelength phonons. Recently, this prediction
of ballistic transport was verified experimentally for both single and multiwalled carbon nan-
otubes [7, 8]. However, theoretical and subsequent experimental verification of the stability
of defects such as pentagon-heptagon pairs (Stone-Wales defects), adatoms and vacancies in
Ts