2 research outputs found
Multiscale Modeling of a Nanoelectromechanical Shuttle
In this article, we report a theoretical analysis of a nanoelectromechanical
shuttle based on a multiscale model that combines microscopic electronic
structure data with macroscopic dynamics. The microscopic part utilizes a
(static) density functional description to obtain the energy levels and
orbitals of the shuttling particle together with the forces acting on the
particle. The macroscopic part combines stochastic charge dynamics that
incorporates the microscopically evaluated tunneling rates with a Newtonian
dynamics.
We have applied the multiscale model to describe the shuttling of a single
copper atom between two gold-like jellium electrodes. We find that energy
spectrum and particle surface interaction greatly influence shuttling dynamics;
in the specific example that we studied the shuttling is found to involve only
charge states Q=0 and Q=+e. The system is found to exhibit two quasi-stable
shuttling modes, a fundamental one and an excited one with a larger amplitude
of mechanical motion, with random transitions between them.Comment: 9 pages, 9 figure
Phosphate structure and lithium environments in lithium phosphorus oxynitride amorphous thin films
Lithium ion-conducting glasses attract wide interest for electrochemical applications like efficient energy storage devices. This work presents a structural study on involved bonding units, based on X-ray photoelectron spectroscopy and infrared spectroscopy, of lithium phosphorus oxide and oxynitride amorphous thin films prepared by RF magnetron sputtering. A thorough consideration of the mid- and far-infrared spectral regions demonstrated structural changes at the phosphate units and the lithium ion environments triggered by nitrogen incorporation and post-deposition thermal treatment. It was found that films prepared by sputtering in pure nitrogen atmosphere have about 75 % of their nitrogen atoms in sites doubly coordinated with phosphorus (P–N=P), and the rest in triply coordinated sites. It was shown also that nitrogen incorporation favors the stability of lithium ions, while annealing enhances ionic conductivity of the oxynitride films