Weak electron-phonon coupling in the early alkali atomic wires

The structural, electronic and vibrational properties of atomic wires composed of the early alkali metals lithium and sodium are studied using density functional perturbation theory. The s-like electronic states near the Fermi level couple very weakly to longitudinal acoustic phonons and not at all to the transverse acoustic phonons, which results in a weak overall electron-phonon coupling. The results are compared to earlier studies on the electron-phonon coupling in metallic atomic wires and reinforces the idea that s-like states at the Fermi level give rise to weak electron-phonon coupling in one-dimension, in contrast with materials containing d-like states at the Fermi level which have correspondingly larger electron-phonon coupling due to interactions with transverse phonons.