E Gnecco et al 2009 Nanotechnology 20 025501 doi:10.1088/0957-4484/20/2/025501
E Gnecco, A Socoliuc1, S Maier2, J Gessler, T Glatzel, A Baratoff and E Meyer
Show affiliationsAtomic-scale friction between a sharp tip at the end of a micro-fabricated silicon cantilever and atomically flat surfaces (NaCl, KBr, HOPG and mica) can be significantly reduced by piezo-induced perpendicular mechanical oscillations at specific resonance frequencies of the cantilever in gentle contact with the sample. The reported measurements confirm and extend the applicability of the effect recently demonstrated using electro-capacitive actuation on alkali halide surfaces in ultra-high vacuum (Socoliuc et al 2006 Science 313 208). A controlled reduction of friction is now observed even on a conductive surface and under ambient conditions, which is quite promising for applications to micro-electromechanical devices. The theory previously used to interpret 'dynamic superlubricity' is supported by new measurements showing that the contact can be maintained in that regime and that the initial reduction of friction is linear versus oscillation amplitude. The calibration of the oscillating component of the normal force is also discussed.
81.40.Pq Friction, lubrication, and wear
62.25.-g Mechanical properties of nanoscale systems
62.20.Qp Friction, tribology, and hardness
85.85.+j Micro- and nano-electromechanical systems (MEMS/NEMS) and devices
Surfaces, interfaces and thin films
Issue 2 (14 January 2009)
Received 13 August 2008, in final form 1 November 2008
Published 9 December 2008
E Gnecco et al 2009 Nanotechnology 20 025501