Possible metallicity in SiO and GeO solids

First principles calculations are performed to determine possible structures and electronic properties of silicon monoxide and germanium monoxide solids. For both compounds, an orthorhombically distorted SnO(s) structure is found to display the highest stability. The bondings in SiO(s) and GeO(s) display considerable degrees of both covalency and ionicity in conjunction with significant metallic character in the bc planes. SiO(s) is predicted to be a better conductor than GeO(s). Possible importance to CMOS technology is emphasized as supposedly insulating thin SiO2(s) layers may display local phase separation, resulting in metallic perforation due to microscopic SiO(s) `spikesʹ.