Plasmonic interferometry: probing launching dipoles in scanning-probe plasmonics

We develop a semi-analytical method for analyzing surface plasmon interferometry using near-field scanning optical sources. We compare our approach to Young double hole interferometry experiments using scanning tunneling microscope (STM) discussed in the literature and realize experiments with an aperture near-field scanning optical microscope (NSOM) source positioned near a ring like aperture slit milled in a thick gold film. In both cases the agreement between experiments and model is very good. We emphasize the role of dipole orientations and discuss the role of magnetic versus electric dipole contributions to the imaging process as well as the directionality of the effective dipoles associated with the various optical and plasmonic sources.Comment: To appear in Journal of Applied Physics (2014

On the imaging of electron transport in semiconductor quantum structures by scanning-gate microscopy: successes and limitations

This paper presents a brief review of scanning-gate microscopy applied to the imaging of electron transport in buried semiconductor quantum structures. After an introduction to the technique and to some of its practical issues, we summarise a selection of its successful achievements found in the literature, including our own research. The latter focuses on the imaging of GaInAs-based quantum rings both in the low magnetic field Aharonov-Bohm regime and in the high-field quantum Hall regime. Based on our own experience, we then discuss in detail some of the limitations of scanning-gate microscopy. These include possible tip induced artefacts, effects of a large bias applied to the scanning tip, as well as consequences of unwanted charge traps on the conductance maps. We emphasize how special care must be paid in interpreting these scanning-gate images.Comment: Special issue on (nano)characterization of semiconductor materials and structure

Models for the Prediction of the Thermal

Five models and eq\1ationsJorthe.predictic;>nof the tbertnal conduc~"ities of powders in the literature are compared with the data obtainedill the experiments of the authors. Anew modified ntodel for the. correlation of the experimental data is presented. Key words: differential scanning calorimetry, porosity, solid content, specific heat, thermal conductivity.Mechanical Engineerin

Imaging Ferroelectric Domains via Charge Gradient Microscopy Enhanced by Principal Component Analysis

Local domain structures of ferroelectrics have been studied extensively using various modes of scanning probes at the nanoscale, including piezoresponse force microscopy (PFM) and Kelvin probe force microscopy (KPFM), though none of these techniques measure the polarization directly, and the fast formation kinetics of domains and screening charges cannot be captured by these quasi-static measurements. In this study, we used charge gradient microscopy (CGM) to image ferroelectric domains of lithium niobate based on current measured during fast scanning, and applied principal component analysis (PCA) to enhance the signal-to-noise ratio of noisy raw data. We found that the CGM signal increases linearly with the scan speed while decreases with the temperature under power-law, consistent with proposed imaging mechanisms of scraping and refilling of surface charges within domains, and polarization change across domain wall. We then, based on CGM mappings, estimated the spontaneous polarization and the density of surface charges with order of magnitude agreement with literature data. The study demonstrates that PCA is a powerful method in imaging analysis of scanning probe microscopy (SPM), with which quantitative analysis of noisy raw data becomes possible

Key factor for hastening the strategic issue diagnosis process: a within organisational model

Previous research on Strategic Issue Diagnosis (SID) had focused on the complexity and novelty associated with the decision-making process in a turbulent environment. What had not been previously addressed in the extant literature is the requirement for speed inherent within the SID process, especially that is related to the gathering of information and facts through an organisation’s environmental scanning procedures. Since proactive management techniques, nimble processes, and systems that allow an organisation to be responsive and build rapid decision-making capabilities are important determinants of success in a turbulent environment, the element of speed associated with SID is an important factor. Our paper identifi es a series of propositions focusing att ention on elements of the environmental scanning processes and management hierarchies that are intended to counteract the recursiveness and redundancy inherent in SID systems and ultimately hasten the strategic decision-making process