Atomistic Simulation of Impurities Segregation to Free Surfaces of α-Al2O3

Abstract

Segregation of di- and trivalent impurities to the (00.1), (01.2) and (11.3) surfaces of α-Al₂O₃ has been investigated using molecular mechanics simulation. In this work, the focus has been on segregation energy calculations depending on impurity size, distance to the surface, and surface coverage. It has been shown the anisotropic segregation of dopants. The segregation energy to the most stable (00.1) surface has the lowest absolute value for all investigated impurities. For trivalent impurities at the (01.2) surface the dependence of the segregation energy on surface coverage has the minimum, which corresponds to the ordered arrangement of dopants. At the (11.3) surface the multilayer segregation has been observed, whereas at the (00.1) and (01.2) surfaces the model of monolayer segregation is acceptable in most studied cases.