An insight to the role of Cr in the process of intrinsic point defects in alpha-Al2O3

Cr is a commonly existing impurity in alpha-Al2O3, and thus the role of Cr in the process of intrinsic point defects in alpha-Al2O3 has been studied based on first-principle calculations. The results show that Cr has significant influence on the formation, charge state, relative stability and equilibrium configuration of isolated intrinsic point defects in alpha-Al2O3, resulting in the variation of defect process. Specifically, depending on the O-condition, the possible defect types, the dominant defects and the defect formation energies will be altered in alpha-Al2O3 after Cr doping. Generally speaking, Cr is favorable for the formation of Schottky defects, Frenkel defects and antisite pairs, giving a different insight to the defect process in alpha-Al2O3.