Physical Origin of Excellent Data Retention over 10years at sub-$\mu \mathrm{A}$ Operation in AgW-Alloy Ionic Memory

We clarify the physical origin of excellent performance and reliability in AgW-alloy ionic memory. AgW-alloy ionic memory shows low operation current in sub- $\boldsymbol{\mu}\mathbf{A}$ range, good data retention and low operation voltage, which are desirable characteristics for high-density cross-point applications. Mechanisms of the improvements in AgW alloy devices compared to pure Ag and AgTi alloy devices are discussed based on first-principles calculations. We find that large cohesive energy of W is a key for improving data retention while keeping low operation voltage in AgW-alloy ionic memory.