First-principles investigation of intrinsic defects and (N, O) impurity atom stimulated Al vacancy in Ti2AlC

Abstract

We use first-principles calculations to study the energetics of intrinsic defects in Ti2AlC and the effect of N or O impurity atoms on the generation of Al vacancies. The insertion of impurity atoms lowers the vacancy formation energy of its neighboring Al. The formation of Al vacancies is related to the experimental observations of growth of AlN or Al2O3 nanowires and nanofibers on the surface of Ti2AlC. Since the growth of these nanostructures is controlled by the generation and migration of intrinsic defects, we propose that a tunable method for synthesis of such nanostructures is possible by controlling impurities.