Strongly {non-Arrhenius} self-interstitial diffusion in vanadium
Publication Type
Journal Article
Year of Publication
2004
Name of Publication
Physical Review B
Volume
70
Pagination
060102
Abstract
We study diffusion of self-interstitial atoms {(SIAs)} in vanadium via molecular-dynamics simulations. The ⟨111⟩-split interstitials are observed to diffuse one-dimensionally at low temperature, but rotate into other ⟨111⟩ directions as the temperature is increased. The {SIA} diffusion is highly {non-Arrhenius.} At T{\textless}600 K, this behavior arises from temperature-dependent correlations. At T{\textgreater}600 K, the Arrhenius expression for thermally activated diffusion breaks down when the migration barriers become small compared to the thermal energy. This leads to Arrhenius diffusion kinetics at low T and diffusivity proportional to temperature at high T.