Non-contact Friction and Relaxational Dynamics of Surface Defects

Abstract

Motion of cantilever near sample surfaces exhibits additional friction even before two bodies come into mechanical contact. Called non-contact friction (NCF), this friction is of great practical importance to the ultrasensitive force detection measurements. Observed large NCF of a micron-scale cantilever found anomalously large damping that exceeds theoretical predictions by 8-11 orders of magnitude. This finding points to contribution beyond fluctuating electromagnetic fields within van der Waals approach. Recent experiments reported by Saitoh et al. (Phys. Rev. Lett. 105, 236103 (2010)) also found nontrivial distance dependence of NCF. Motivated by these observations, we propose a mechanism based on the coupling of cantilever to the relaxation dynamics of surface defects. We assume that the surface defects couple to the cantilever tip via spin-spin coupling and their spin relaxation dynamics gives rise to the backaction terms and modifies both the friction coefficient and the spring constant. We explain the magnitude, as well as the distance dependence of the friction due to these backaction terms. Reasonable agreement is found with the experiments.

5 pages, 4 figures, accepted for publication in Physical Review Letters

References in corpus (7)

• Model for l/f Flux Noise in SQUIDs and Qubits
• Magnetism in SQUIDs at Millikelvin Temperatures
• Dangling-bond spin relaxation and magnetic 1/f noise from the amorphous-semiconductor/oxide interface: Theory
• Dissipative Van der Waals interaction between a small particle and a metal surface
• Adsorbate induced enhancement of electrostatic non-contact friction
• Microscopic Model of Critical Current Noise in Josephson Junctions
• Gigantic Maximum of Nanoscale Noncontact Friction

Cited by in corpus (12)

• Nanomechanical Resonators: Toward Atomic Scale
• CDW slips and giant frictional dissipation peaks at the NbSe${}_2$ surface
• Mechanical dissipation from charge and spin transitions in oxygen deficient SrTiO_3
• Atomic scale friction of molecular adsorbates during diffusion
• Reconstruction of Tip-Surface Interactions with Multimodal Intermodulation Atomic Force Microscopy
• Spatially resolved surface dissipation over metal and dielectric substrates
• Noncontact frictional force between surfaces by peristaltic permittivity modulation
• Damping of a nanocantilever by paramagnetic spins
• Force-detected Magnetic Resonance Imaging of Influenza Viruses in the Overcoupled Sensor Regime
• Motion-induced spin transfer
• Optimising motion-induced spin transfer
• Differential Magnetic Force Microscopy with a Switchable Tip