Related papers: Simultaneous current-, force- and work function me…
Current-density-functional theory is used to calculate ionization energies of current-carrying atomic states. A perturbative approximation to full current-density-functional theory is implemented for the first time, and found to be…
The thesis explores calculating tunneling current densities between planar conducting electrodes in an STM. It considers factors like bias voltages and the separation between electrodes, using Fermi energy and work functions. Pauli blocking…
We present the design, fabrication and discuss the performance of a new combined high-resolution Scanning Tunneling and thermopower Microscope (STM/SThEM). We also describe the development of the electronic control, the user interface, the…
Atomic force microscopy is based on tip sample interaction, which is determined by the properties of tip and sample. Unfortunately, in particular in ambient conditions the tip as well as the sample are contaminated, and it is not clear how…
Properties of typical MEMS materials have been widely investigated. Mechanical properties of MEMS structures depend not only on the bulk material properties, but also structural factors. A measurement system has been made to measure…
We investigate a semiclassical momentum density energy functional for atoms and show that it yields the same value as the well-known Thomas-Fermi functional. In fact, we show an explicit relation between the minimizers of the two…
We find that the jump-into-contact of the cantilever in the atomic force microscope (AFM) is caused by an inherent instability in the motion of the AFM cantilever. The analysis is based on a simple model of the cantilever moving in a…
We consider the stochastic dynamics of an array of two closely spaced atomic force microscope cantilevers in a viscous fluid for use as a possible biomolecule sensor. The cantilevers are not driven externally, as is common in applications…
Measurements with an atomic force microscope (AFM) offer a direct way to probe elastic properties of lipid bilayer membranes locally: provided the underlying stress-strain relation is known, material parameters such as surface tension or…
The Work function (f)is fundamental for chemistry and electronics. Additionally, f can be used to examine the validity of the theoretical surfaces by comparing it with experimental f, even in the absence of long-range orders. In the…
The functionalization of an Atomic Force Microscope (AFM) cantilever with a colloidal bead is a widely used technique when the geometry between the probe and the sample must be controlled, particularly in force spectroscopy. But some…
We present an alternative approach to pump-probe spectroscopy for measuring fast charge dynamics with an atomic force microscope (AFM). Our approach is based on coherent multifrequency lock-in measurement of the intermodulation between a…
We present a four-point probe resistance measurement technique which uses four equivalent current measuring units, resulting in minimal hardware requirements and corresponding sources of noise. Local sample potentials are measured by a…
We introduce a novel control mode for Scanning Tunneling Microscopy (STM) that leverages di/dz feedback. By superimposing a high-frequency sinusoidal modulation on the control signal, we extract the amplitude of the resulting tunneling…
Stepped well-ordered semiconductor surfaces are important as nanotemplates for the fabrication of one-dimensional nanostructures which are candidates of intriguing electronic properties. Therefore a detailed understanding of the underlying…
Electron emission can be utilised to measure the work function of the surface. However, the number of significant digits in the values obtained through thermionic-, field- and photo-emission techniques is typically just two or three. Here,…
We have constructed a scanning tunneling potentiometry system capable of simultaneously mapping the transport-related electrochemical potential of a biased sample along with its surface topography. Combining a novel sample biasing technique…
Thermal fluctuation of the cantilever position sets a fundamental limit for the precision of any Scanning Force Microscope. In the present work we analyse how these fluctuations limit the determination of the resonance frequency of the…
The Planar Model of the Electrode-Vacuum-Electrode configuration for STM in which electrode surfaces are assumed to be infinite parallel planes, with atomic size separation and vacuum between them, is used to calculate tunneling current…
Acoustic tweezers enable non-contact manipulation of microscale objects, but quantitative in situ evaluation of the peak local pressure amplitude remains difficult in confined devices. Conventional hydrophone-based measurements are often…