团簇与电极之间的接触距离对铝硅团簇的非平衡输运性质的影响  

Transport Properties of Binary Clusters

作　　者：万海青[1] 卞祖武[1] 

机构地区：[1]南昌师范高等专科学校,江西南昌330029

出　　处：《江西教育学院学报》2009年第3期13-16,共4页Journal of Jiangxi Institute of Education

摘　　要：文章用第一性原理非平衡格林函数方法探讨了铝硅团簇:Al2、Si2、Al4和AlSi置于两个铝电极之间时的输运性质。结果发现团簇的输运性质受体系的纳米结构和团簇与电极之间的接触距离双重影响。通过计算非平衡性质,我们发现所有的团簇在低偏压下表现出金属性而在高偏压下表现出非线性行为。特别是Al2和AlSi团簇在距离d=3.5A°时,表现出明显的负微分电阻现象(NDR)。电流最大值与最小值之比约为16,显示出分子开关特性。上述结果表明:分子导体和电极的接触距离的精确确定和具体的分子导体的电子结构的讨论对正确地预言或考察分子导体的非平衡输运性质具有极其重要的意义。We present first principles studies on the transport properties of small silicon and aluminum clusters： Al2, Si2, Al4 and AlSi sandwichs between two Al（100） electrodes. The variation of the current-voltage characteristics as a function of contact distance for these two-probe systems is probed. The results show that the transport properties are dependent On both the specific nanostructure and the separation distance between the central molecule and the electrodes. For currentvoltage characteristics, all the clusters show the metallic behaviour at lower bias. However,a very direrent non-linear behaviour can be observed at higher bias. For AlSi and Al2, when the distance between the central cluster and the electrodes is 3.5A, large negative direrential resistance （NDR） can be found in the bias range 0.8 V-1.4 V. A switch ratio about 16 is obtained,which can be used as a molecular switch.

关 键 词：透射谱 负微分电阻 分子开关 

分 类 号：O441.6[理学—电磁学]