Scaling laws of structural lubricity.
"Structural lubricity" refers to a unique friction state in which two flat surfaces are sliding past each other with ultralow resistance due to incommensurate atomic lattice structures. In this case, theory anticipates sublinear scaling for the area dependence of friction. Here, we experimentally confirm these predictions by measuring the sliding resistance of amorphous antimony and crystalline gold nanoparticles on crystalline graphite. For the amorphous particles a square root relation between friction and contact area is observed. For crystalline gold particles we find a more complex scaling behavior related to variations in particle shape and orientation. These results allow us to link mesoscopic friction to atomic principles.
Institute of Applied Physics (IAP), Justus-Liebig-Universität Giessen, 35392 Giessen, Germany.
Dirk
D
Dietzel
Institute of Applied Physics (IAP), Justus-Liebig-Universität Giessen, 35392 Giessen, Germany.
Michael
M
Feldmann
Department of Mechanical Engineering and Materials Science and Center for Research on Innovative Structures and Phenomena (CRISP), Yale University, New Haven, Connecticut 06520-8284, USA.
Udo D
UD
Schwarz
Physikalisches Institut and Center for Nanotechnology (CeNTech), Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
Harald
H
Fuchs
Institute of Applied Physics (IAP), Justus-Liebig-Universität Giessen, 35392 Giessen, Germany.
André
A
Schirmeisen