稳定的单层蜂窝状二氧化硅结构
Stable single-layer honeycomb like structure of silica
摘要：
二氧化硅或SiO $_2$是地球岩石的主要成分，具有几个3D复杂的结晶和非晶相，但它在3D中不具有石墨状层状结构。我们的理论分析和数值计算从第一性原理预测一个单层蜂窝状的同素异形体，h $α$ -二氧化硅，它可以被看作是来自硅烯的氧化，它具有有趣的原子结构与重入键角的六边形。它是一种宽禁带半导体材料，在外加电场作用下，具有显著的机电性能，表现出几何形状的变化。特别地，它是具有负泊松比的拉胀超材料，并且具有高压电系数。虽然它可以形成稳定的双层和多层结构，但其纳米带可以根据其手性显示金属或半导体行为。外来吸附原子对悬挂Si轨道的覆盖可以将新的功能性归因于h $α$ -二氧化硅。特别地，Si $_2$ O $_5$（其中Si原子被来自顶侧和底侧的氧原子交替地饱和）可以经历结构转变以制备硅质，另一种稳定的二氧化硅单层结构。
英文摘要：
Silica or SiO$_2$, the main constituent of earth's rocks has several 3D complex crystalline and amorphous phases, but it does not have a graphite like layered structure in 3D. Our theoretical analysis and numerical calculations from the first-principles predict a single-layer honeycomb like allotrope, h$α$-silica, which can be viewed to be derived from the oxidation of silicene and it has intriguing atomic structure with re-entrant bond angles in hexagons. It is a wide band gap semiconductor, which attains remarkable electromechanical properties showing geometrical changes under external electric field. In particular, it is an auxetic metamaterial with negative Poisson's ratio and has a high piezoelectric coefficient. While it can form stable bilayer and multilayer structures, its nanoribbons can show metallic or semiconducting behavior depending on their chirality. Coverage of dangling Si orbitals by foreign adatoms can attribute new functionalities to h$α$-silica. In particular, Si$_2$O$_5$, where Si atoms are saturated by oxygen atoms from top and bottom sides alternatingly can undergo a structural transformation to make silicatene, another stable, single layer structure of silica.
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