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Advances in Tribology
Volume 2013, Article ID 850473, 11 pages
http://dx.doi.org/10.1155/2013/850473
Research Article

Atomistic Frictional Properties of the C(100)2x1-H Surface

1Seagate Technology LLC, 40710 Kato Road, Fremont, CA 94538, USA
2Western Digital Corporation, 5863 Rue Ferrari, San Jose, CA 95138, USA
3Seagate Technology LLC, Recording Heads Operations, 7801 Computer Avenue South, Bloomington, MN 55435, USA

Received 3 August 2012; Accepted 5 November 2012

Academic Editor: Bruno Marchon

Copyright © 2013 Paul M. Jones et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Density functional theory- (DFT-) based ab initio calculations were used to investigate the surface-to-surface interaction and frictional behavior of two hydrogenated C(100) dimer surfaces. A monolayer of hydrogen atoms was applied to the fully relaxed C(100)2x1 surface having rows of C=C dimers with a bond length of 1.39 Å. The obtained C(100)2x1-H surfaces (C–H bond length 1.15 Å) were placed in a large vacuum space and translated toward each other. A cohesive state at a surface separation of 4.32 Å that is stabilized by approximately 0.42 eV was observed. An increase in the charge separation in the surface dimer was calculated at this separation having a 0.04 e transfer from the hydrogen atom to the carbon atom. The Mayer bond orders were calculated for the C–C and C–H bonds and were found to be 0.962 and 0.947, respectively. σ C–H bonds did not change substantially from the fully separated state. A significant decrease in the electron density difference between the hydrogen atoms on opposite surfaces was seen and assigned to the effects of Pauli repulsion. The surfaces were translated relative to each other in the (100) plane, and the friction force was obtained as a function of slab spacing, which yielded a 0.157 coefficient of friction.