中文摘要：

采用基于第一性原理和非平衡格林函数的输运计算方法,研究了4个原子宽度锯齿（zigzag）型纳米带在边界掺Be原子时对输运性质的影响.结果发现：石墨纳米带呈半导体特性,杂质原子抑制了附近原子的局域磁性,改变了完整纳米带的电子结构,2种自旋电子将表现出不同的透射情况,且在费米面附近尤为明显.通过计算散射区的分子自洽哈密顿量（MPSH）能谱,发现2种自旋电子能级不再简并,在外加偏压下纳米带产生自旋极化电流.同时,在偏压低于1.5 V时,其中1种自旋电子出现负微分电阻现象（NDR）.

英文摘要：

Based on a combined method of first principle and non-equilibrium Green′s function theory for calculating transport property,the Be doping effect in the graphene nanoribbion with 4 atom width and with zigzag edges were studied.It was found that the graphene nanoribbon was semiconductor.The impurity atom could suppress the local magnetism and changed the electronic structure of perfect nanoribbon.The two spin components behaved differently in its transmission property,especially near Fermi energy.By solving the energy spectrum of molecular self-consistent Hamiltonian（MPSH）,it was found that the degeneracy between two spin components was broken,thus spin-polarized current was generated under external bias.Meanwhile,when the bias voltage was lower than 1.5 V,negative differential resistance（NDR） behavior was found for one spin component.