Direct space representation of metallicity and structural stability in SiO solids

Abstract

First principles calculations are performed on possible structures of silicon monoxide solids. The chemical character of all of the bonding interactions is systematically quantified in real space. It is found that the most stable SiO structure possesses the highest number of inequivalent bond paths. This process reveals a novel metallic Si-Si interaction and provides an explanation for the origin of the unexpectedly high conductivity in thin silicon oxide layers. In this paper a new measure for quantifying metallic character (in direct space) present in a bond has been introduced. Furthermore it has been possible to determine the directional properties of this metallic character in real space using the charge density. This finding is very important for future complementary metal oxide semiconductor technology.