  Thin nanowires of silicon oxide were studied by pseudopotential density
functional electronic structure calculations using the generalized gradient
approximation. Infinite linear and zigzag Si-O chains were investigated. A wire
composed of three-dimensional periodically repeated Si4O8 units was also
optimized, but this structure was found to be of limited stability. The
geometry, electronic structure, and Hirshfeld charges of these silicon oxide
nanowires were computed. The results show that the Si-O chain is metallic,
whereas the zigzag chain and the Si4O8 nanowire are insulators.
