Peierls Instability and Electron-Phonon Coupling in a One-dimensional Sodium Wire

We have studied Peierls instability in an atomically thin wire of sodium atoms using first-principles density-functional methods. A Na wire has a stable uniform linear structure over a range of inter-atomic distances. At smaller inter-atomic distances it develops a zigzag distortion. At larger inter-atomic distances, just before breaking, a Na wire undergoes a very weak Peierls dimerization. This behavior of a Na wire is understood in terms of its electron-phonon coupling properties.