2001 Volume 42 Issue 11 Pages 2253-2256
First-principles calculations of electron-transport properties for a single-row atomic wire of Na under the application of a finite bias voltage are presented. Calculations are carried out by a density functional Green-function approach based on the Lippmann-Schwinger equation and the Landauer-Büttiker formula to evaluate the conductance. The model consists of a linear wire, a pair of jellium electrodes and two pyramidal clusters as the interface between the linear wire and the jellium electrode. As a result of the calculations, we found that the voltage drop is generated neither in the pyramidal clusters nor in the jellium electrodes, but in the linear wire. The conductance of Na atomic wire evaluated from the electron transmission is about 84% of the quantized unit 2e2⁄h, and this low conductance is caused by partial reductions of the transmission in some parts of the incident energies. The main reason for this reduction is that the spatial distributions of some states responsible for electron transport become discontinuous around the linear wire in the case of applying a finite bias voltage.