石墨烯带―苯环―石墨烯带结构的电子输运
The Properties of Electron Transport in the Structure of Graphene Nanoribbon-Benzene Ring-Graphene Nanoribbon

用非平衡格林函数和密度泛函理论相结合的第一性原理计算了石墨烯带-苯环-石墨烯带结构的伏安特性和电流噪声,发现苯环和石墨烯导线不同的连接方式给出的电子输运和电流噪声性质有显著不同,1-4连接下电流显著大于1-3连接.在研究量子器件时,量子噪声是不同于热噪声的,它是分析器件结构常用的一种手段.研究发现这2种结构的散粒噪声和Fano因子也完全不同,对于1-3结构Fano因子接近1,而对于1-4结构,Fano因子相对就较小.
Based on the nonequilibrium Green?s function approach and density functional theory, the I-V curve and shot noise of the structure of graphene nanoribbon-benzene ring-graphene nanoribbon were studied by ab initio method. It was found that different connections of grapheme ribbons with the benzene ring gives very different results. Symmetrical 1-4 connection gives much larger current compared with the asymmetry 1-3 connection. The shot noise and Fano factor were also calculated. Fano factor approaches to one for the asymmetrical 1-3 connection, while the symmetrical 1-4 connection gives smaller Fano factor. It was confirmed that different from the thermal noise, shot nose can be used as a method of analyzing the transport properties of the quantum structures