Metal Nanotips Research Articles

Real-space formulation of the quantum-mechanical elastic diffusion undern-fold axially symmetric forces

The field emission from a metal nanotip is studied because of its relevance to the Fresnel projection microscope. This study required the development of a numerical treatment of the $n$-fold axially symmetric Schr\odinger equations.

The electronic structure of transition metal interacting tip and sample and atomic force microscopy. II

For pt. I see ibid., vol. 7, p. 6625 (1995). A detailed theoretical study of the interaction of transition metal nanotips with surfaces is performed in the tight-binding scheme. The real space recursion method is used to determine the local densities of states (LDOS) of the interacting tips and samples. We consider more especially W supported pyramidal tips with different morphologies. The interaction of W supported tips with W(001) surfaces is studied within the intermediate-interaction regime for which metallic adhesive forces are dominant. The electronic structure of both the tip and the sample are found to be substantially modified due to the tip/sample (T/S) interaction. The T/S interaction energy curves are also calculated when the tip's apex is located above high-symmetry surface sites. It is shown that the T/S interaction energy can be reproduced with a good accuracy using the model of a square LDOS. Finally, we present a simple numerical scheme to obtain atomic force images. We study the influence of the tip's morphology and of the surface's defects on the contrast of the resulting images.

The electronic structure and stability of transition metal nanotips. I

A detailed theoretical study of the electronic structure of transition metal nanotips is performed in the tight-binding scheme. The real space recursion method is used to determine the local densities of states (LDOS) of the nanotips. We consider more especially the W supported pyramidal tips and W pyramidal clusters with different morphologies. The apex LDOS of perfect supported tips are found to be quite different from those of surfaces and of clusters having the same morphology. The stability of the supported nanotips of different morphologies is also examined.