Since the 1980s, atomic force microscopy (AFM) has rapidly developed into a versatile, high-resolution characterization technique, available in a variety of imaging modes. Within intermittent-contact tapping-mode, imaging bistability and sample mechanical damage continue to be two of the most important challenges faced daily by AFM users. Recently, a new double-control-loop tapping-mode imaging...

Magnetic skyrmions are particle-like topological excitations in ferromagnets, which have the topo-logical number Q = ± 1, and hence show the skyrmion Hall effect (SkHE) due to the Magnus force effect originating from the topology. Here, we propose the counterpart of the magnetic skyrmion in the antiferromagnetic (AFM) system, that is, the AFM skyrmion, which is topologically protected but witho...

The atomic force microscope system (AFM) has become a popular and useful instrument to measure the intermolecular forces with atomic resolution that can be applied in electronics, biological analysis, materials, semiconductors, etc. This paper studies the bifurcation phenomenon and complex nonlinear dynamic behavior of the probe tip between the sample and microcantilever of an atomic force micr...

We develop a statistical framework for the quantitative characterization and analysis of force-extension curves obtained from single-molecule force spectroscopy (SMFS) measurements. We apply this methodology to force-extension data obtained for elastinlike polypeptides (ELPs) with precisely engineered molecular architectures, where we demonstrate that our approach enables SMFS to be used to stu...

Alkali-Antimonide growth was examined at the Center of Functional Nanomaterials (CFN) at Brookhaven National Laboratory (BNL). The materials were grown in a UHV chamber and analyzed by means of core-level xray electron spectroscopy (XPS) and UHV-atomic-force microscopy (UHV-AFM). We were able to grow CsK2Sb cathodes with an average quantum efficiency around 12.5 % under good vacuum conditions.T...

A novel method for reconstituting sperm chromatin was used to investigate how protamine 1 condenses DNA. Complexes formed in vitro using linearized plasmid DNA were imaged and measured by atomic force microscopy (AFM). The structures formed were found to be highly dependent on the sample preparation method used for reconstitution. Interstrand, side-by-side fasiculation of DNA and toroidal-like ...

One of the key goals in atomic force microscopy (AFM) imaging is to enhance material property contrast with high resolution. Bimodal AFM, where two eigenmodes are simultaneously excited, confers significant advantages over conventional single-frequency tapping mode AFM due to its ability to provide contrast between regions with different material properties under gentle imaging conditions. Bimo...

Title of dissertation: MECHANICAL CHARACTERIZATION OF NORMAL AND CANCEROUS BREAST TISSUE SPECIMENS USING ATOMIC FORCE MICROSCOPY Rajarshi Roy Dissertation directed by: Professor Jaydev P. Desai Department of Mechanical Engineering, Robotics, Automation, and Medical Systems (RAMS) Laboratory. Breast cancer is one of the most common malignancies among women worldwide. Conventional breast cancer d...