Columnar-to-Disk Structural Transition in Nanoscale (SiO2)N Clusters

Abstract

Extensive large-scale global optimizations refined by ab initio calculations are used to propose ( SiO 2 ) N N = 14 - 27 ground states. For N < 23 clusters are columnar and show N − odd - N − even stability, energetically and electronically. At N = 23 a columnar-to-disk structural transition occurs reminiscent of that observed for Si N . These transitions differ in nature but have the same basis, linking the nanostructural behavior of an element (Si) and its oxide ( SiO 2 ). Considering the impact of devices based on the nanoscale manipulation of Si / SiO 2 the result is of potential technological importance.