First-principles investigation of the conductive filament configuration in rutile TiCh_(2-x)ReRAM

摘要

The interactions and ordering of oxygen vacancies in rutile TiO_2 were thoroughly investigated by density functional calculations to search for atomic configurations of the conductive filament. As random isolated vacancies could not support the low-resistance state conduction in TiO_2 ReRAM, vacancy ordering was introduced in [110] and [001] directions of the lattice to study the electronic structures. The calculation results revealed that a di-vacancy chain in [001] direction makes the electrons delocalized in that direction, which is identified as a possible configuration of the conductive filament. This low-resistance state can be effectively disrupted by moving oxygen vacancies out of the filament to reach high-resistance states.