Selector Only Memory: Exploring Atomic Mechanisms from First-Principles

The recent attention to Ovonic threshold switching (OTS) materials is owed to the development of the so-called selector-only memory (SOM) concept. Understanding the SOM switching mechanism at the atomic scale is required to facilitate device optimization. With first-principles simulations, we identify two possible atomistic mechanisms leading to mobility gap changes and hence threshold voltage modulation, which determines the memory window (MW) of SOM: i) local atomic bond rearrangement or ii) atomic segregation, depending on the operating conditions. Our findings provide an atomic-level perspective that confirms previous high-level modelling assertions about the working principles of OTS and SOM.