四聚噻吩分子结的自旋输运性质  

Spin transport properties of quaterthiophene molecular junctions

作　　者：严深浪[1] 龙孟秋[2] 黄伟荣[3] 徐慧[1,2] 

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083 [2]中南大学物理与电子学院,湖南长沙410083 [3]长沙理工大学物理与电子科学学院,湖南长沙410004

出　　处：《中南大学学报（自然科学版）》2013年第11期4436-4441,共6页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(21103232);湖南省研究生科研创新项目(CX2011B110)

摘　　要：利用第一性原理计算方法和非平衡格林函数理论,研究四聚噻吩连接在两个半无限长磁性镍电极间组成的分子结的电荷输运性质,考察电极磁性在平行和反平行构型下的自旋输运性质。研究结果表明:无论是平行自旋构型还是反平行自旋构型,电流都发生了明显的自旋极化现象,且平行自旋注入系数高于反平行,并随着电压增大呈现先增大后减小的趋势;不同自旋构型对分子最低非占据态轨道的扩展性的影响,是影响自旋注入效率和电荷输运性质的主要原因。Using first principles calculation methods in combination with nonequilibrium Green＇s function theory, the electronic transport properties of molecular junctions constructed by a single quarterthiophene molecular connected to two semi-infinite magnetic nickel electrodes were investigated. The spin transport properties with the electrodes magnetic parallel and anti-parallel configuration were studied. The results show that the spin-polarized can be observed both for parallel and anti-parallel spin configuration, and the spin injection coefficient ofprarllel is larger than that o-f anti-parallel, which increases firstly, and then decreases with the increase of the voltage. The varying of spin injection efficiency and charge transport properties mainly result from the delocalization of lowest unoccupied molecular orbital, which is determined by the different spin configuration.

关 键 词：四聚噻吩 第一性原理 分子结 自旋输运 

分 类 号：O469[理学—凝聚态物理]