Tunneling junctions under finite bias voltages: Ab initio calculations of electron densities and currents

Electronic structures of bielectrode junctions under external bias voltages were recently solved numerically on an ab initio basis using nonequilibrium Green's function methods in combination with the density functional theory. Here we examine this technique by applying it to two electrodes within a jellium model separated by a vacuum layer. We investigate the charge distribution, the shape of the tunnel barrier and the current. Our results suggest, that this method is valid only in a limited range of external bias voltages. (C) 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.