Fe effect on the process of intrinsic point defects in α-Al2O3

Fe is a common existing impurity in α-Al2O3, and thus the effect of Fe on the process of intrinsic point defects in α-Al2O3 has been investigated based on first-principles calculations. It is found that the formation, charge state, relative stability and equilibrium configuration of isolated intrinsic point defects in α-Al2O3 will be remarkably influenced by Fe, resulting in the variation of defect process, i.e., the formation of defect complex such as Schottky defect, Frenkel defect and antisite pair in α-Al2O3. Generally speaking, depending on the O-condition, the most stable configurations, types and relative proportions of defect complexes will be varied by Fe doping in α-Al2O3. From the viewpoint of defect formation energy, Fe is favorable for Frenkel defects and antisite pairs in α-Al2O3 under both O-rich and O-deficient conditions; while for Schottky defects, Fe is favorable for the defect formation under the O-rich condition, yet unfavorable under the O-deficient condition.