Study of Interstitial Atom Diffusion in Nanowire using Diffusion Equation driven by Chemo-Mechanical Potential

Abstract

Impurity atom distribution and its time evolution in cylindrical nanowire were studied using a diffusion equation based on chemo-mechanical potential, which considered coupling effects between chemical potential (chemical effect) and internal stress (mechanical effect) due to interstitial impurity atoms. We did consider diffusion blocking and nanowire yielding effects when we solved the diffusion equation. The yield criterion was described by comparing local volumetric strain caused by impurity atoms with critical volumetric strain at which the lattice instability appears. Obtained results used the diffusion equation with realistic materials parameters indicate a possibility of nanowire yielding due to interstitial atom diffusion and diffusion slowdown due to the yielding.