Linear monatomic wires stabilized by alloying:Ab initiodensity functional calculations

Using ab initio density functional calculations, we find that the monatomic AuZn and AuMg alloy wires have a truly linear structure as stable as the zig--zag one which is prone to form two-dimensional structures. The energy barrier between these two phases is about 0.7 eV for AuZn wire and 0.5 eV for AuMg wire. The injection of s electrons into the gold wire by zinc or magnesium lifts the Fermi level and the resulting $s--p$ hybridization yields an energy minima for the linear structure, which is further stablized by the polarization effect arisen from the enhanced atomic charges.