Formation Energy of Point Defects in Free Surfaces and Grain Boundaries in MgO

摘要

The computer code developed in recent years at Argonne National Laboratory for the investigation of the energy and structure of interfaces in ionic crystals has been extended to permit the consideration of neutral intrinsic point defects in such interfaces. As examples, bound Schottky pairs as well as substitutional Fe exp 2+ and Ca exp 2+ impurities are considered in the (100) surface and surface region. The role of isovalent impurities in the free (110) surface region and in a coincident-site twist boundary are also investigated. Results are compared and found in agreement with results obtained by means of the HADES program. (ERA citation 08:024000)