title: Frequency modulated atomic force microscopy on MgO(001) thin films: interpretation of atomic image resolution and distance dependence of tip-sample interaction.
abstract: Atomically resolved images on a MgO(001) thin film deposited on Ag(001) obtained in ultrahigh vacuum by frequency modulated atomic force microscopy at low temperature are presented and analysed. Images obtained in the attractive regime show a different type of contrast formation from those acquired in the repulsive regime. For the interpretation of the image contrast we have investigated the tip-sample interaction. Force and energy were recovered from frequency shift versus distance curves. The derived force curves have been compared to the force laws of long-range, short-range and contact forces. In the attractive regime close to the minimum of the force-distance curve elastic deformations have been confirmed. The recovered energy curve has been scaled to the universal Rydberg model, yielding a decay length of l = 0.3 nm and ΔE = 4.2 aJ (26 eV) for the maximum adhesion energy. A universal binding-energy-distance relation is confirmed for the MgO(001) thin film.
authors: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin, Germany.
authors: M
authors: M
authors: Heyde
authors: M
authors: M
authors: Sterrer
authors: H-P
authors: HP
authors: Rust
authors: H-J
authors: HJ
authors: Freund