First-principles calculation method of electron-transport properties of metallic nanowires

We report the development of an efficient and sophisticated procedure for calculating the first-principles electronic structure and current flow of a nanometre-scale system (e.g. nanowire) sandwiched by two truly semi-infinite bulks. The solution of the Kohn-Sham equation of this system is so constructed as to joint generalized Bloch functions inside the left and right bulks together by matching them across the interfacial region between the bulks. The formalism is described quite simply in the real-space finite-difference approach within the framework of the density functional theory, and thus the wavefunction-matching scheme is easily realized without any troublesome process. The efficiency and accuracy of the method are illustrated by evaluating the electric conductance of a single-row gold nanowire attached to the semi-infinite Au(100) electrodes.