Non-contact friction

Abstract

Our understanding of friction and mechanism of energy dissipation has undoubtedly experienced a tremendous profit after the introduction of scanning probe microscopy. Nowadays the tribological response of a sliding asperity can be easily traced down to the atomic scale. Still, many important aspects of friction on the nanoscale are scarcely studied. Among them we can easily recognize the dissipation accompanying the motion of a nano-object in close proximity to a solid surface. An example, which is quite suitable for experimental investigations, is given by the oscillations of a tiny pendulum. Here we report on different mechanisms of energy loss—for instance probably the most common Joule dissipation. Next we demonstrate that pendulum oscillations are expected to induce both phononic and electronic excitations in the underlying surface and the clear distinction between them is possible while working over metal/superconductor phase transition. Finally, we describe an example of coupling ofmechanical oscillator to the charge-density-wave phase, an exquisitely subtle long-range order property of matter.