2006 APS March Meeting
Monday–Friday, March 13–17, 2006;
Baltimore, MD
Session R32: Focus Session: Computational Nanoscience V
2:30 PM–5:30 PM,
Wednesday, March 15, 2006
Baltimore Convention Center
Room: 329
Sponsoring
Units:
DCOMP DMP
Chair: Wenchang Lu, North Carolina State University
Abstract ID: BAPS.2006.MAR.R32.4
Abstract: R32.00004 : Dissipation of Mechanical Energy in Carbon Nanotube-based Mechanical Devices
3:06 PM–3:42 PM
Preview Abstract
Abstract
Author:
Paul Tangney
(The Molecular Foundry, Lawrence Berkeley National Laboratory)
The creation of functional mechanical devices at the nanoscale is
a major goal of nanoscience, and multiwalled carbon nanotubes (MWCNT)
are promising materials for constructing such devices. The large
disparity between the strengths of intralayer and interlayer
interactions
in MWCNTS allows for smooth relative motion of concentric tubes.
Some simple mechanical elements such as linear and rotational
bearings
have already been constructed from MWCNTs by exploiting this
feature[1].
However, little is known about the dominant mechanisms for
dissipation of
mechanical energy at the nano scale, and devices based on MWCNTs
are both
technologically important and useful as test systems for theoretical
investigations. In this talk, atomistic simulations of some simple
MWCNT-based mechanical systems will be presented. It is shown that
reducing the dimensions of a device can have a strong impact on
phononic
friction. The small masses of nanotubes relative to the forces
between them
means that relative velocities can be comparable to and larger
than atomic
thermal velocities. In this regime, theories based on a
quasi-adiabatic
response of atoms to the relative motion of nanotubes fail and
simulations
reveal a strong and complex velocity dependence of friction[2].
Large edge
to surface ratios mean that edges can play an important role in
energy
dissipation and for concentric nanotubes of length 10s of nm, the
ends of the
nanotubes have been shown to dominate sliding friction[2]. These
and other
important features of friction in nanotube-based devices will be
discussed
and illustrated with the results of molecular dynamics simulations.
This work was supported by the NSF Grant No. DMR04-39768 and U.S.
DOE Contract No. DE-AC03-76SF00098.
[1] J. Cumings and A. Zettl, Science 289, 602 (2000); A. M.
Fennimore et al., Nature 424, 408 (2003).
[2] P. Tangney, S. G. Louie, and M. L. Cohen, Phys. Rev. Lett.
93,065503
(2004) ; P. Tangney, M. L. Cohen, and S. G. Louie, to be published.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2006.MAR.R32.4