Density functional theory insight into metal ions and vacancies for improved performance in storage devices
Umbreen Resheed, Turki Alsuwian, Muhammad Imran, Hassan Algadi, Ejaz Ahmad Khera, R.M. Arif Khalil, Chandreswar Mahata, Fayyaz Hussain
Abstract
Metal ions and oxygen vacancies (Vo) in resistive switching (RS) material play a crucial role in nonvolatile low power consuming memory devices. Performed first principle calculations investigate the impact of Cu dopant as well as collective effect of Cu + Vo on cubic ATiO3 (A = Ba, Be and Mg). Utilization of GGA + U for including coulombic effect with nonlocal exchange and exchange correlation functional has made the results more accurate. Structural properties, defect states formation in the bandgap region, and formation energy have been studied. Orbital contributions of each atom in valance band and conduction band region have been determined to explore the influence of Cu doping and Cu + Vo on electronic properties of optimized ATiO3. Among the studied materials, BeTiCuO3 + Vo is found to have least oxygen vacancy formation energy (EOVFE) and highest conductivity. The clustering of Vo around the dopant is noted, which leads to the formation of conducting filaments (CFs). These CFs play pivotal role in switching mechanism for low potential RRAM and allied devices.