First-principles molecular dynamics study for average structure and oxygen diffusivity at high temperature in cubic Bi2O3

Bismuth oxide, Bi2O3, has a cubic structure (δ-phase) at high temperature. High oxygen conductivity of δ-Bi2O3 should be closely related to disordering of the oxygen sublattice. In order to reconstruct the disordered structure in the crystal using first-principles molecular dynamics (FPMD), a sufficiently long simulation time is essentially required. In this study, the FPMD simulation up to 1 ns is performed with special interest given to the convergence of the average structure and the oxygen diffusivity with respect to the simulation time. The obtained average structure and the oxygen diffusivity are in good agreement with those obtained by experimental analysis.