Atomic and Electronic Structure of Defect Ni Complexes and Oxygen Vacancies in HfO2 and Their Influence on Charge Transport in Memristors

Abstract

This study is devoted to theoretical investigation of the atomic and electronic structure of defect complexes formed by nickel atoms and oxygen vacancies in HfO₂ using the density functional theory. We consider Ni in the interstitial position as well in the Hf substitution position. It is shown that Ni facilitates the formation of oxygen vacancies and their clusterization. The localization of charge carriers occurs predominantly at oxygen vacancies, while nickel produces an indirect effect on the charge transport. Complexes of nickel and oxygen vacancies do not form shallow traps. It is shown that filamentary structures in the form of continuous chains in HfO₂ do not exhibit metal-type conductivity.