Coherent-potential approach for the zero-temperature DC conductance of weakly disordered narrow systems

Abstract

The configurationally averaged zero-temperature DC conductance of weakly disordered systems of finite width is calculated using the coherent-potential approximation. There is no smooth transition from the quantised quasi-ballistic regime at low disorder to the structureless conductance for larger disorder. Instead the conductance oscillates as a function of the Fermi energy in the intermediate region. The perturbation theory agrees well with the numerical results obtained previously.