CPM Seminar

The Materials Machine:
Nanostructure Growth from the Vapor Phase

Daniel Gall

Rensselaer Polytechnic Institute

An ongoing challenge in materials physics is to arrange atoms in a controlled manner in order to design materials with desired physical properties. This requires to develop (1) tools that predict materials properties solely from their elemental composition and atomic arrangement and (2) synthesis methods which control the assembly on an atomic level. I will illustrate these two aspects of materials physics by discussing nanostructure growth from the vapor phase, focusing on transition metal nitrides.

An atomistic understanding of growth is developed using a multiple length-scale and dimensionality approach which combines experimental and computational methods to investigate microstructural evolution of entire layers, surface roughening and island kinetics, and single atom and molecule diffusion and reaction processes. Atomic shadowing, anisotropic surface diffusion, and ion-surface interactions are exploited to create unique nanostructures, including nanopipes, nanostaircases, nanosprings, and nanorods, with potential applications as sensors, hard self-lubricating coatings, and gas filtration. Mechanical, optical, vibrational, and electronic transport properties are determined experimentally and understood using ab initio electronic structure calculations. This understanding leads, in turn, to the controlled synthesis of novel semiconductors, superconductors, ultra-hard coatings, magnetic insulators, and conducting refractory compounds.