Theoretical study of the defect distribution of trivalent cation impurities in MgO

Atomistic simulation techniques have been used to calculate defect energies for a range of trivalent cation impurities in MgO single crystals. From these, values of the association energies have been estimated for impurity-vacancy aggregates ranging in size from simple impurityvacancy monomers, containing one impurity ion, to large clusters containing up to 24 impurity ions. For the MgO:Cr3+ system, these energies have been incorporated in a mass-action analysis and predictions made of the dependence of the equilibrium distribution of defects on temperature and on the nominal concentration of the dopant.

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