Density functional theory study of the effect of helium clusters on tritium-containing palladium lattices

N. K. Das, N. H. De Leeuw

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Density functional theory (DFT) calculations have been employed to calculate the energetics, structures and migration behaviour of helium in palladium tritides. Increasing the tritium concentration in palladium leads to a decrease in the formation energies of helium clusters, indicating that He clusters can form in the lattices. The calculated results show less lattice expansion in Pd defect-containing lattices compared to the perfect lattice owing to smaller lattice distortions. The lowest energy migration path for helium diffusion is along octahedral-tetrahedral-octahedral sites but the energy barrier increases with increasing tritium concentration. Repulsive interactions occur between Pd d and He s orbitals, suggesting that displacement of the metal atoms in the lattice leads to growth of pressure inside the lattices. This process may change the microstructural properties leading to the degradation of the material.

Original languageEnglish
Article number475002
JournalJournal of Physics Condensed Matter
Volume27
Issue number47
DOIs
Publication statusPublished - 2015 Oct 13

Keywords

  • DFT simulations
  • Helium cluster
  • Migration
  • Pd defects
  • Tritium concentration

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

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