We have developed a dynamic force microscope DFM working in a novel operation mode which is referred to as phase modulation atomic force microscopy PM-AFM . PM-AFM utilizes a fixed-frequency excitation signal to drive a cantilever, which ensures stable imaging even with occasional tip crash and adhesion to the surface. The tip-sample interaction force is detected as a change of the phase differ...

Using a hard sphere model and numerical calculations, the effect of the hydration force between a conical tip and a flat surface in the atomic force microscope (AFM) is examined. The numerical results show that the hydration force remains oscillatory, even down to a tip apex of a single water molecule, but its lateral extent is limited to a size of a few water molecules. In general, the contrib...

In an effort to improve sub-molecular imaging precision, a general distributed-based modeling approach for the atomic force microscope system is proposed which allows for the design of a stabilizing controller/estimation scheme that stabilizes the micro-cantilever based system while asymptotically identifying the atomic interaction force. That is, the estimated interaction force asymptotically ...

A novel nonlinear fractional order sliding mode controller is proposed to control the chaotic atomic force microscope system in presence of uncertainties and disturbances. In the design of the suggested fractional order controller, conformable fractional order derivative is applied. The stability of the scheme is proved by means of the Lyapunov theory based on conformable fractional order deriv...

We perform extensive first-principles calculations to simulate the topographical atomic-force-microscope image of an adatom on the Si(111)-(7 x 7) surface, demonstrating the feasibility of imaging not only the atoms but also the atomic orbitals. Our comparative study of tip terminations shows that two subatomic features can appear for a single adatom when it is imaged by a Si(001)-type tip havi...

We report a simple technique that allows obtaining mid-infrared absorption spectra with nanoscale spatial resolution under low-power illumination from tunable quantum cascade lasers. Light absorption is detected by measuring associated sample thermal expansion with an atomic force microscope. To detect minute thermal expansion we tune the repetition frequency of laser pulses in resonance with t...

A combined Raman and atomic force microscope (AFM) microscope has been installed at beamline P01, PETRA III, DESY in Hamburg and is now available for all users of this beamline. With this unique setup 57 Fe nuclear resonance scattering and simultaneously performed Raman or Atomic Force Microscopy experiments are possible. Here we report on technical details of this new sample environment and on...