Abstract: The current-voltage (I-V) characteristics and the transmission spectrums of zigzag graphene nanoribbon with different spin-configurations are investigated by using the first-principles calculations. It is shown that the current-voltage curves and the transmission spectrums strongly depend on the spin-configurations of the two sides of the ribbon. For the spin-parallel configuration structure, the curve is linear under lower bias voltage; For the spin-antiparallel configuration structure, there is a strong spin-polarization-dependent transmission which implies the ribbon can be used as a spin filter; while for other spin-configurations structures, the curve has the characteristic of semiconductor. It is found that there is a large magneto-resistance(MR) when the bias voltage is small. The impurity in the central scattering region significantly influences the spin-dependent current and the spin filter efficiency, which may lead the large MR to disappear.

Key words: graphene nanoribbon,  electronic transport,  first-principles