Charge localization on the hexa-interstitial cluster in MgO.

Density functional theory was used to study the effects of charge localization on the structure and mobility of the highly mobile hexa-interstitial cluster in MgO. It was found that the relative stability of the configurations changed as charge was localized, with the higher energy intermediate configuration of the neutral cluster becoming the lowest energy configuration for the doubly charged cluster. The singly charged cluster was found to have the lowest migration barrier, with a barrier of 0.18 eV. The high mobility of the singly charged hexa-interstitial cluster could have a significant effect on microstructure evolution following radiation damage, while the detailed properties will be sensitive to the level of doping in the material.