Scientific Achievement
Researchers in the Electronic Materials Program showed that hydrogen faces three times higher energy barrier and over one order of magnitude lower diffusivity when it diffuses across a metal-insulator phase boundary in VO2.
Significance and Impact
Retarded atomic diffusion is expected to exist universally in all phase transformations where the transformation temperature is coupled to chemical composition, and inspires new ways to engineer dopant diffusion in phase-coexisting material systems.
Research Details
- Observed a chemical analogy of super-elasticity, where the 2nd derivative of Gibbs energy (chemical susceptibility) diverges at the transition point, leading to an anomalously high energy barrier for dopant diffusion in coexisting phases
- Additional energy barrier attributed to a volumetric energy penalty that the diffusers need to pay for the latent heat reduction
Publication Details
Y. Cai, Z. Wang, J. Wan, J. Li, R. Guo, J.W. Ager, A. Javey, H. Zheng, J. Jiang, J. Wu, Nature Communications (2024).
