Direct diffusion through interpenetrating networks: Oxygen in titanium

TL;DR

This study uses first-principles methods to identify multiple oxygen diffusion pathways in titanium, revealing that diffusion occurs through interconnected networks without a single dominant transition.

Contribution

It uncovers multiple oxygen interstitial sites and diffusion pathways in titanium, challenging previous models that assumed unstable lattice sites.

Findings

Identified three stable oxygen interstitial sites in titanium.

Quantified multiple interconnected diffusion networks.

No single transition dominates oxygen diffusion.

Abstract

How impurity atoms move through a crystal is a fundamental and recurrent question in materials. The previous understanding of oxygen diffusion in titanium relied on interstitial lattice sites that were recently found to be unstable, making the diffusion pathways for oxygen unknown. Using first-principles quantum-mechanical methods, we find three oxygen interstitial sites in titanium, and quantify the multiple interpenetrating networks for oxygen diffusion. Surprisingly, no single transition dominates, but all contribute to diffusion.