Noncontact friction and force fluctuations between closely spaced bodies -art. no. 096801

Noncontact friction between a Au(111) surface and an ultrasensitive gold-co ated cantilever wag measured as a function of tip-sample spacing, temperatu re, and bias voltage using observations of cantilever damping and Brownian motion. The importance of the inhomogeneous contact potential is discussed and comparison is made to measurements over dielectric surfaces. Using the fluctuation-dissipation theorem, the force fluctuations are interpreted in terms of near-surface fluctuating electric fields interacting with static s urface charge.