Realization of the Switching Mechanism in Resistance Random Access   Memory (RRAMTM) Devices: Structural and Electronic Properties Affecting   Electron Conductivity in Halfnium Oxide-Electrode System through First   Principles Calculations
  Resistance Random Access Memory (RRAMTM) device, with its electrically induced nanoscale resistive switching capacity, has been gaining considerable attention as future non-volatile memory device. Here, we propose a mechanism of switching based on oxygen vacancy migration-driven change in electronic properties of the transition metal oxide (TMO) film stimulated by set pulse voltages. We used density functional theory (DFT)-based calculations to account for the effect of oxygen vacancy and its migration on the electronic properties of HfO2 and Ta/HfO2 systems, and thereby create the entire story on RRAMTM's switching mechanism. Computational results on the activation energy barrier for oxygen vacancy migration were found to be consistent with the results of set and reset pulse voltage obtained from experiment. Understanding of this mechanism would be beneficial to effectively realize materials design in these devices. 
Susan Me\~nez Aspera, Hideaki Kasai, Hirofumi Kishi, Nobuyoshi Awaya,   Shigeo Ohnishi, and Yukio Tamai
cond-mat.mtrl-sci