title: Tuning the instability in static mode atomic force spectroscopy as obtained in an AFM by applying an electric field between the tip and the substrate.
abstract: We have investigated experimentally the role of cantilever instabilities in determination of the static mode force-distance curves in presence of a dc electric field. The electric field has been applied between the tip and the sample in an atomic force microscope working in ultra-high vacuum. We have shown how an electric field modifies the observed force (or cantilever deflection)-vs-distance curves, commonly referred to as the static mode force spectroscopy curves, taken using an atomic force microscope. The electric field induced instabilities shift the jump-into-contact and jump-off-contact points and also the deflection at these instability points. We explained the experimental results using a model of the tip-sample interaction and quantitatively established a relation between the observed static mode force spectroscopy curves and the applied electric field which modifies the effective tip-sample interaction in a controlled manner. The investigation establishes a way to quantitatively evaluate the electrostatic force in an atomic force microscope using the static mode force spectroscopy curves.
authors.affiliation: DST Unit for NanoSciences, Department of Materials Science, S.N.Bose National Centre for Basic Sciences, Kolkata 700 098, West Bengal, India. somaready@gmail.com
authors.forename: Soma
authors.initials: S
authors.lastname: Biswas
authors.forename: A K
authors.initials: AK
authors.lastname: Raychaudhuri
authors.forename: P A
authors.initials: PA
authors.lastname: Sreeram
authors.forename: Dirk
authors.initials: D
authors.lastname: Dietzel