Open-framework sodium silicides have been attracted great attention for their outstanding physical properties, as well as potential candidates to obtain fascinating metastable Si allotrope for the practical use. In this work, the pressure-composition phase diagram of the Na-Si system (NaSi_x, x=1-8) within the pressure range of 0-20 GPa has been performed via the global structure search coupled within the framework of density functional theory. We found eight NaSi_x structures with open-channels that are composed of the polygonal Si lattices and filled with Na atoms. The predicted NaSi_x compounds are dynamically stable at high pressures by exhibiting metallic behaviors. The finding of new open-framework NaSi_x structures significantly improves the understanding of the relationship between crystal structures and electronic properties of sodium silicide compounds at high pressures.

开放骨架的硅化钠由于其出色的物理性能以及获得实用的迷人亚稳硅同素异形体的潜在候选物而备受关注。在这项工作中，通过在密度泛函框架内耦合的全局结构搜索，完成了在0-20 GPa压力范围内的Na-Si系统（NaSi _x，x = 1-8）的压力组成相图。理论。我们发现了八个具有开放通道的NaSi _x结构，这些结构由多边形Si晶格组成，并充满了Na原子。预测的NaSi _x化合物通过表现出金属行为在高压下动态稳定。新的开放框架NaSi _x的发现 的结构大大提高了人们对高压下硅化钠化合物的晶体结构与电子性能之间关系的理解。