AVS 45th International Symposium
    Nanometer-scale Science and Technology Division Thursday Sessions
       Session NS-ThP

Paper NS-ThP6
Metallic Adhesion at the Atomic Scale

Thursday, November 5, 1998, 5:30 pm, Room Hall A

Session: Nanometer-Scale Science and Technology Division Poster Session
Presenter: A. Schirmeisen, McGill University, Canada
Authors: A. Schirmeisen, McGill University, Canada
G. Cross, McGill University, Canada
P. Grütter, McGill University, Canada
U. Dürig, IBM Research Division, Switzerland
Correspondent: Click to Email
A unique AFM / STM / FIM system operating in UHV has been shown to measure directly force interactions of an atomically defined tip-sample junction. A W(111) tip, terminated by only three atoms, approaching an atomically flat Au(111) surface showed structural stability even upon touching the surface. The measured force distance curves reveal adhesion peaks of 5 nN and a contact stiffness of about 40 N/m. Moreover, there are no indications of a jump to contact. The yield strength of the junction (maximum contact pressure divided by the tip radius) reaches values of up to 25 GPa. The observed metallic short range adhesion forces show substantial contributions over an unexpectedly large distance range, which can not be explained within in the standard model for metallic adhesion by Ferrante and Smith.@footnote 1@ This study is being extended to different tip materials. First results of an Ir tip approaching a Au surface will be presented. Furthermore, to complement this study, MD simulations were performed at Tampere University by J. Nieminen. @FootnoteText@ @footnote 1@ J.H.Rose, J.R.Smith, J.Ferrante, Phys.Rev.B 28, 1835 (1983)