Density Functional Simulation of a Breaking Nanowire

We study the deformation and breaking of an atomic-sized sodium wire using density functional simulations. The wire deforms through sudden atomic rearrangements and smoother atomic displacements. The conductance of the wire exhibits plateaus at integer values in units of ${2e}^2/h$ corresponding to a specific number of eigenchannels. The transitions between plateaus can be abrupt in connection with structural rearrangements or extend over a few Å of elongation. The interplay between conductance modes and structural deformation is discussed by means of the eigenchannel transmission probabilities.