title: Structural depinning of Ne monolayers on Pb at T < 6/5 K.
abstract: We have studied the nanofriction of Ne monolayers with a quartz-crystal microbalance technique at temperatures below 6.5 K and in ultrahigh-vacuum conditions. Very homogeneous and smooth lead electrodes have been physically deposited on a quartz blank at 150 K and then annealed at room temperatures. With such a Pb-plated quartz-crystal microbalance, we have observed a pronounced depinning transition separating a low-coverage region, where the film is nearly locked to the oscillating electrode, from a high-coverage region characterized by slippage at the solid-fluid boundary. Such a behavior has been found to be very reproducible. These data are suggestive of a structural depinning of the solid Ne film when it becomes incommensurate with the lead substrate, in agreement with the results of an extensive molecular-dynamics study.
authors.affiliation: Dipartimento di Fisica G. Galilei, Università di Padova, via Marzolo 8, 35131 Padova, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Bruschi
authors.forename: G
authors.initials: G
authors.lastname: Fois
authors.forename: A
authors.initials: A
authors.lastname: Pontarollo
authors.forename: G
authors.initials: G
authors.lastname: Mistura
authors.forename: B
authors.initials: B
authors.lastname: Torre
authors.forename: F
authors.initials: F
authors.lastname: Buatier de Mongeot
authors.forename: C
authors.initials: C
authors.lastname: Boragno
authors.forename: R
authors.initials: R
authors.lastname: Buzio
authors.forename: U
authors.initials: U
authors.lastname: Valbusa