This group works on the fabrication and mechanical deformation of nanostructures, primarily one-dimensional nanowires and nanorods. In addition, our study covers the structure evolution of materials under radiation and aging.

One example is the predictive modeling of nanostructure fabrication. By integrating three pieces of fundamental physics – surface diffusion, geometrical shadowing, and twin formation – we have proposed a concept of self-organized branching. Further, using atomistic simulations we have demonstrated the feasibility of such concept. Finally, a subsequent experiment has validated the simulation results. Shown on the right are the proposal and the experimental validation.

Along this line, we also experimentally explore the fabrication of nanowires, as shown on the far right.

Nano Lett ‘05 Nanotechnology ‘07

The second example shows a close tie between surface science and nanomechanics. Using a combination of density-functional-theory ab initio calculations, classical molecular dynamics simulations, and analytical formations, we show that (1) elastic constants of nanostructures can be larger or smaller than their bulk counterparts (figure on the right), and (2) structure transformation occurs due to surface stress, which could be assisted by additional external mechanical loading (figure on the far right).

Appl Phys Lett ’04 Appl Phys Lett ‘07

The final example is the development of an atomistic model. Through mathematical mapping, we have developed an atomistic simulator that is capable of simulating fabrication processes over seconds in time scale, at the atomic level, 500 nm in linear dimension, and in three-dimensional space. Shown on the right are textured nanocolumns and thin films.

Handbook Mater Model ‘05 J Appl Phys ‘98