Zigzag equilibrium structure in monatomic wires

Abstract

We have applied first-principles density-functional calculations to the study of the energetics, and the elastic and electronic properties of monatomic wires of Au, Cu, K, and Ca in linear and a planar-zigzag geometries. For Cu and Au wires, the zigzag distortion is favorable even when the linear wire is stretched, but this is not observed for K and Ca wires. In all the cases, the equilibrium structure is an equilateral zigzag (bond angle of 60$^{\rm o}$). Only in the case of Au, the zigzag geometry can also be stabilized for an intermediate bond angle of 131$^{\rm o}$. The relationship between the bond and wire lengths is qualitatively different for the metallic (Au, Cu and, K) and semiconducting (Ca) wires.Comment: 4 pages with 3 postscript figures. To appear in Surf. Science (proceedings of the European Conference on Surface Science, ECOSS-19, Madrid Sept. 2000