Defect Processes, Phase Transformations, and Nanoscale Phenomena in Complex Ceramics
EMSL Project ID
17292
Abstract
This project aims to provide computational insights into defect processes, hydrogen and helium interactions, and phase transformations in a number of oxides and wide band-gap semiconductors. The work will focus on defects in silicon carbide (SiC), gallium nitride (GaN), pyrochlore (Gd2ZrxTi2-xO7) and fluorite-structure oxides (ZrO2 and CeO2). A multiscale modeling approach that combines insights from ab initio calculations with longer scale simulations using molecular dynamics and kinetic Monte Carlo methods will be employed using the computational chemistry code NWChem, molecular dynamics codes such as DL_POLY and MDCASK, and kinetic Monte Carlo codes developed at PNNL. This modeling effort will address the production of atomic-level defects in displacement cascades, migration of defects, hydrogen transport, He migration and interaction with defects, the formation and evolution of nitrogen bubbles and gallium nanowires in GaN, annealing of defect clusters, chemistry of solid-liquid and solid-solid interfaces, phase transformations both in the bulk and at interfaces, and nanoscale phenomena in oxides.
Project Details
Project type
Exploratory Research
Start Date
2005-12-19
End Date
2007-01-11
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Devanathan, R and W J Weber, Dynamic Annealing of Defects in Irradiated Zirconia-Based Ceramics, J. Materials Research 23 [3]: 593-597 (2008).
Devanathan R, J Yu, and WJ Weber, Energetic Recoils in UO2 Simulated using Five Different Potentials, J. Chemical Physics 130 [17]: 174502, 1-9 (2009).
Gao F, WJ Weber, HY Xiao, and XT Zu, Formation and Properties of Defects and Small Vacancy Clusters in SiC: Ab Initio Calculations, Nucl. Instrum. and Methods in Physics Res. B 267 [18]: 2995-2998 (2009).
Moreira PAFP, R Devanathan, J Yu, and WJ Weber, Molecular Dynamics Simulation of Threshold Displacement Energies in Zircon, Nucl. Instrum. and Methods in Physics Res. B 267 [20]: 3431-34536 (2009).
Posselt M, F Gao, and H Bracht. 2008. "Correlation between self-diffusion in Si and the migration mechanisms of vacancies and self-interstitials: An atomistic study." Physical Review. B, Condensed Matter 78:035208. doi:10.1103/PhysRevB.78.035208
Wang Z, XT Zu, L Yang, F Gao, and WJ Weber. 2008. "Orientation and temperature dependence of the tensile behavior of GaN nanowires: an atomistic study." Journal of Materials Science. Materials in Electronics 19(8-9):863-867. doi:10.1007/s10854-007-9526-8
Yu J, R Devanathan, and WJ Weber. 2009. "First-principles study of defects and phase transition in UO2." Journal of Physics. Condensed matter 21(43):Art. No. 435401. doi:10.1088/0953-8984/21/43/435401
Yu J, R Devanathan, and WJ Weber, Unified Interatomic Potential for Zircon, Zirconia and Silica Systems, J. Materials Chemistry 19 [23]: 3923-3930 (2009).