非磁性掺杂下石墨烯纳米带的自旋输运

摘要

Non-linear spin transport properties in edge doped ZGNRs of different width are studied systematical⁃ly employing the density functional theory combined with the Green's functions. When an aluminum or a phos⁃phorus atom is doped at the edges of the ZGNRs, the electrons transport properties show strong spin effects. In particular, in the Al doped ZGNRs, the up-spin current increases monotonously with the bias voltage while the NDR effect occurs in the down spin current around the bias voltage 1.0V. The calculations of transmission spec⁃tra indicate that the Al(P) atom which substitutes the edge C atom works as a donor (an acceptor) impurity. This results in the spin polarization of conductance and the appearance of a main transmission valley above (below) the Fermi level.%　　基于第一性原理的密度泛函理论和非平衡格林函数方法，研究了边界掺杂下锯齿型石墨烯纳米带（ZGNRs）中的自旋输运性质，结果显示：在ZGNRs边缘，利用单个铝（Al）或磷（P）原子替换碳原子后，ZGNRs中的电子输运呈现强烈的自旋效应。特别地，在Al掺杂的偶数个原子宽度的ZGNRs中，上自旋电流随着电压单调增长，而下自旋电流在1伏偏压左右出现明显的负微分电阻效应（NDR）。其主要原因是替换边缘C原子的Al （P）原子为施主（受主）杂质，一方面使透射谱或电导发生自旋极化，另一方面在透射谱上杂质态在费米能之上（下）引入了一个透射谷。