Effects of stick–slip motions on Besocke-style scanners in scanning probe microscopes

Abstract

In Besocke-style scanners, a theoretical model with stick–slip sliding boundary conditions is presented by Timoshenko beam theory combined with the harmonic-balance method. The flexural vibration characteristics of the piezo-tubes induced by the stick–slip motions of the ball on the rail are investigated. The results show that the flexural vibrations essentially depend on the ratio of the ball–rail lateral friction threshold to the product of the ball–rail lateral contact stiffness and the vibration amplitude of the ball. When the ratio changes from zero to one, the lateral friction applied to the ball induces complex flexural vibrations. The vibrations can be regulated by adjusting an input electric signal to change the vibration amplitude of the ball, or using an external electro-magnetic force to change the preload of the ball–rail interaction, or changing the radius of the ball. Thus, the adverse vibrations of Besocke-style scanner can be eliminated to improve the spatial resolution of the atomic structure in scanning probe microscopes.