\emph{Ab initio} Calculations for Hydrogen-Doped HfO$_{2-x}$ RRAM

Hydrogen impurities are shown to have significant effects on the mechanism of electronic conduction in HfO$_2$-based resistance change memory (RRAM) devices, and to affect the ionic transport during the forming, set, and reset processes. Using density functional theory and employing the LDA+\emph{U} formalism, the diffusion of oxygen ions in hydrogen-doped HfO$_{2-x}$ was examined and its implications on the electronic structure are determined. Results indicate that hydrogen can have multiple substantial effects on device operation, and has a strong potential to improve device switching and uniformity. These hydrogen-doped devices make promising candidates for low-voltage and forming-free memory schemes, as well as for electronic synapses in neuromorphic systems.