Static frictional forces at crystalline interfaces

D. J. Diestler, E. Rajasekaran, X. C. Zeng

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

A statistical thermodynamic description of the atomic force microscope is developed and used to compute the force of static friction for a single-atom tip on a hexagonal close-packed substrate surface under constant load in vacuum. The substrate atoms are taken to be independent isotropic harmonic oscillators, and the tip-substrate interaction is taken to be Lennard-Jones (12,6). Movement of the tip is treated as a quasistatic (reversible) process. The force of static friction (i.e., the maximum of the component of the force parallel to the direction of movement of the tip) is computed by the Monte Carlo technique for several crystallographic directions (paths) and found to be strongly anisotropic. The frictional force is minimum along a particular path where rows of substrate atoms form a "groove"; it is up to 2 orders of magnitude greater for the path perpendicular to the groove. The dependence of the frictional force on the hardness of the substrate (as measured by the force constant of the substrate harmonic potential) and on temperature was examined for these two extreme paths. For hard substrates the frictional force is nearly linear with load. As the substrate gets softer, or as the temperature increases at fixed hardness, the frictional force declines. The results of the computations are correlated with recent experimental observations on the sliding of nanocrystals of MoO3 over an MoS2 substrate.

Original languageEnglish (US)
Pages (from-to)4992-4997
Number of pages6
JournalJournal of Physical Chemistry B
Volume101
Issue number25
StatePublished - Jun 19 1997

Fingerprint

Crystalline materials
Substrates
static friction
grooves
Atoms
hardness
Hardness
Friction
atoms
Statistical mechanics
Nanocrystals
harmonic oscillators
sliding
nanocrystals
Microscopes
microscopes
Vacuum
harmonics
Temperature
thermodynamics

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Diestler, D. J., Rajasekaran, E., & Zeng, X. C. (1997). Static frictional forces at crystalline interfaces. Journal of Physical Chemistry B, 101(25), 4992-4997.

Static frictional forces at crystalline interfaces. / Diestler, D. J.; Rajasekaran, E.; Zeng, X. C.

In: Journal of Physical Chemistry B, Vol. 101, No. 25, 19.06.1997, p. 4992-4997.

Research output: Contribution to journalArticle

Diestler, DJ, Rajasekaran, E & Zeng, XC 1997, 'Static frictional forces at crystalline interfaces', Journal of Physical Chemistry B, vol. 101, no. 25, pp. 4992-4997.
Diestler DJ, Rajasekaran E, Zeng XC. Static frictional forces at crystalline interfaces. Journal of Physical Chemistry B. 1997 Jun 19;101(25):4992-4997.
Diestler, D. J. ; Rajasekaran, E. ; Zeng, X. C. / Static frictional forces at crystalline interfaces. In: Journal of Physical Chemistry B. 1997 ; Vol. 101, No. 25. pp. 4992-4997.
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