Theoretical computation of the quantum transport of zigzag mono-layer Graphenes with various z-direction widths

The quantum transport computations have been carried on four different width of zigzag graphene using a nonequilibrium Green’s function method combined with density functional theory. The computed properties are included transmittance spectrum, electrical current and quantum conductance at the 0.3V as bias voltage.  The considered systems were composed from one-layer graphene sheets differing with each other in y-direction width. The number of unit cells for considered graphenes are one, three, five and seven in z-direction, whiles the scattering region and first super cells of semi-infinite right and left electrodes were formed from three unit cell in z-direction. At the first the considered structures have been optimized and next the NEGF calculations were carried out on the optimized structures. All of the computations have been done using OPENMX3.6 atomic scale simulation code.  The results were presented and interpreted for the considered systems in terms of the z-direction width of studied graphenes.