Room-temperature diffusion of metal clusters on graphene.

We study the diffusion dynamics, the diffusion mechanisms, and the adsorption energetics of Ag, Au, Cu, and Pd dimers, as well as of Ag trimers on single-layer graphene (SLG) by means of ab initio molecular dynamics (AIMD) simulations and density-functional theory (DFT) calculations. The simulations show that Ag, Cu, and Au clusters exhibit a super-diffusive pattern characterized by long jumps, which can be explained by the flat potential energy landscape (PEL) (corrugation of a few tens of meV) encountered by those clusters on SLG. Pd dimers, instead, diffuse in a pattern that is reminiscent of conventional random walk, which is consistent with a significantly rougher PEL of the order of 100 meV.

In Situ and Real-Time Nanoscale Monitoring of Ultra-Thin Metal Film Growth Using Optical and Electrical Diagnostic Tools.

Continued downscaling of functional layers for key enabling devices has prompted the development of characterization tools to probe and dynamically control thin film formation stages and ensure the desired film morphology and functionalities in terms of, e.g., layer surface smoothness or electrical properties.

Anomalous versus Normal Room-Temperature Diffusion of Metal Adatoms on Graphene.

Fabrication of high-performance heterostructure devices requires fundamental understanding of the diffusion dynamics of metal species on 2D materials. Here, we investigate the room-temperature diffusion of Ag, Au, Cu, Pd, Pt, and Ru adatoms on graphene using and classical molecular dynamics simulations. We find that Ag, Au, Cu, and Pd follow Lévy walks, in which adatoms move continuously within ∼1-4 nm domains during ∼0.

Ab initio study of effects of substitutional additives on the phase stability of γ-alumina.

Using ab initio calculations, we have evaluated two structural descriptions of γ-Al(2)O(3), spinel and tetragonal hausmannite, and explored the relative stability of γ-Al(2)O(3) with respect to α-Al(2)O(3) with 2.5 at.% of Si, Cr, Ti, Sc, and Y additives to identify alloying element induced electronic structure changes that impede the γ to α transition.