The Role of the Electrode Size of to the Elecronic Transport Properties

Abstract

We study the size effects of the electrode to the elecronic transport properties via a molecule of benzene sandwiched between two graphene electrodes using an ab initio nonequilibrium Green's function method and density function theory. More specially, two types of electrodes are selected: one ring wide electrodes and two rings wide electrodes. We find that the current cross the system that is with two rings wide electrodes is bigger than the current that is with one ring wide electrodes. Detailed analyses of the projected density of states and the transmission spectra of the system reveals the mechanism: with wider electrodes, transmission coeffients walk nearer to the fermi energy and may make contribution to the current at applied bias voltages.