First Principles Calculation of Universal Conductance Fluctuation in Monatomic Metal Chains

Combining the non-equilibrium Green's function method and density functional theory, we provide a first-principle scheme to calculate the universal conductance fluctuation (UCF) in quasi one-dimensional monatomic chains subject to a magnetic field. Our results show that for these monatomic chains, the amplitude of the UCF is much smaller than the previous theoretical prediction for mesoscopic conductors by Lee et al. Phys. Rev. Lett. 55 (1985) 1622; Phys. Rev. B 35 (1987) 1039] The reason is that the ergodic hypothesis fails in these nanowires due to the confinement of geometry. We ascribe the phenomenon to the flux-dependent density of states fluctuation.