碳掺杂硅原子链电子输运性质的第一性原理计算  

The Calculation on the Electronic Transport Properties of Si Chain Doped C Atom from First Principles

作　　者：文萍[1] 周亚鑫[1] 唐纲[1] 程晓洪[1,2] 柳福提[1,2] 

机构地区：[1]宜宾学院物理与电子工程学院,四川宜宾644007 [2]宜宾学院计算物理四川省高校重点实验室,四川宜宾644007

出　　处：《宜宾学院学报》2013年第12期42-45,71,共5页Journal of Yibin University

基　　金：地方高校国家级大学生创新创业训练项目资助(201210641105);四川省教育厅科研项目基金(13ZB0207)

摘　　要：运用密度泛函理论结合非平衡格林函数方法,对5个Si原子构成的链耦合在Au（100）之间所形成的三明治结构的纳米结点的电子输运性质进行了第一性原理计算,结果得到在两极距离为20.556 A时,几何结构最稳定,此时平衡电导为0.711G0（=2e2/h）;在此稳定结构中,把中间的一个Si原子替换成C原子后,其平衡电导为1.344Go.电子主要是通过Si原子链的p电子轨道进行传输的.在-1.0～1.0V的电压范围内,随着正负偏压的增大,电导减小;在相同电压下,掺C后的Si链的电导比未掺杂Si链的电导大,即掺C能有效提高Si链的电子传输性能.The electronic transport properties of silicon atomic chain, which is made up of 5 silicon atoms, sandwiched between Au electrodes, were investigated with combination of density functional theory and the non-equilibrium green＇ s function method. The structure of the geometry of nanoscle junctions in different distance was optimized. The calculation shows that when the dis- tance between two electrodes is 20. 556 A, the geometric structure of nanoscale junctions is the most stable one. The equilibrium conductance is 0. 711 GO （ = 2e2/h）. When the silicon atom at the middle of the chain was replaced with a carbon atom at equilib- rium position, the conductance is 1. 344 G0. The transmission channel is mainly composed of p orbits electrons of carbon and sili- con. The conductance calculation of the nanoscale junctions at the equilibrium position under different external voltage from -1.0 to 1.0 V reveal that the conductance decreases gradually with the external bias increases. At the same voltage, the conductance of silicon chain doped carbon is larger than that of pure silicon atomic chain. It indicates that doping carbon atom in the silicon chain can improve the conductance.

关 键 词：掺杂 硅链 电子输运 密度泛函理论 非平衡格林函数 

分 类 号：O469[理学—凝聚态物理]