title: Gigantic maximum of nanoscale noncontact friction.
abstract: We report measurements of noncontact friction between surfaces of NbSe2 and SrTiO3 and a sharp Pt-Ir tip that is oscillated laterally by a quartz tuning fork cantilever. At 4.2 K, the friction coefficients on both the metallic and insulating materials show a giant maximum at the tip-surface distance of several nanometers. The maximum is strongly correlated with an increase in the spring constant of the cantilever. These features can be understood phenomenologically by a distance-dependent relaxation mechanism with distributed time scales.
authors.affiliation: Department of Physics, Faculty of Science and Technology, Keio University, Yokohama 223-8522, Japan.
authors.forename: Kohta
authors.initials: K
authors.lastname: Saitoh
authors.forename: Kenichi
authors.initials: K
authors.lastname: Hayashi
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Shibayama
authors.forename: Keiya
authors.initials: K
authors.lastname: Shirahama