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It is worth understanding the potentials of zero charge (PZCs) and structures of stepped metal/water interfaces, because for many electrocatalytic reactions, stepped surfaces are more active than atomically flat surfaces. Herein, a series of stepped Pt/water interfaces are modeled at different step densities with ab initio molecular dynamics. It is found that the structures of Pt/water interfaces are significantly influenced by the step density, particularly in regard to the distribution of chemisorbed water. The step sites of metal surfaces are more preferred for water chemisorption than terrace sites, and until the step density is very low, water will chemisorb on the terrace. In addition, it is revealed that the PZCs of stepped Pt/water interfaces are generally smaller than that of Pt(111), and the difference is mainly attributed to the difference in their work function, providing a simple way to estimate the PZCs of stepped metal surfaces. Finally, it is interesting to see that the Volta potential difference is almost the same for Pt/water interfaces with different step densities, although their interface structures and magnitude of charge transfer clearly differ. [ABSTRACT FROM AUTHOR]

Selectors with an excellent performance exhibit great potential to achieve a high integration density and contribute to the design of peripheral systems. However, the uniformity and stability need to be optimized. We demonstrate a high-performance ZrO2/NbOx threshold switching selector that exhibits a low-threshold voltage, ultra-high uniformity, and excellent voltage stability. The oxygen storage properties of the tunneling layer cause a thinner NbO2 region and optimize the performance, which is confirmed by thermal simulations and compositional analyses. The conduction mechanism of the OFF state is fit and verified to be Schottky emission. Compared with the reference device, the tunneling device has a smaller Schottky distance, which indicates a thinner NbO2 region. This work provides an effective method to improve the performance of the selector and understand its physical mechanism. [ABSTRACT FROM AUTHOR]