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 Peierls transition in a Na wire is associated with a large increase in electron–phonon coupling.