Effect of electron and hole doping on the structure of C, Si, and S nanowires

We use ab initio density functional calculations to study the effect of electron and hole doping on the equilibrium geometry and electronic structure of C, Si, and S monatomic wires. Independent of doping, all these nanowires are found to be metallic. In absence of doping, C wires are straight, whereas Si and S wires display a zigzag structure. Besides two preferred bond angles of 60\ifmmode^\circ\else\textdegree\fi{} and 120\ifmmode^\circ\else\textdegree\fi{} in Si wires, we find an additional metastable bond angle of 90\ifmmode^\circ\else\textdegree\fi{} in S wires. The equilibrium geometry and electronic structure of these nanowires is shown to change drastically upon electron and hole doping.