【摘要】 用基于密度泛函理论的非平衡格林函数方法研究了水分子对7个碳原子组成的一维原子链的输运性质的影响.碳原子链放在具有有限截面的Al(100)电极中.研究发现,碳原子链上的水分子的数目和放置的位置的不同将对体系输运性质产生很大的影响.特别是,单个H2O分子对碳链平衡电导的影响随其摆放位置的不同而出现奇偶振荡,例如,当位于奇数编号的碳原子上时,电导取极大值,当位于偶数编号的碳原子上时,取极小值.将两个H2O分子置于不同的碳原子正上方时,在不同的位置平衡电导相差很大,在某些特殊的情况下原本受到抑止的第三个本征通道也有较大的贡献.此外,还研究了放置两个水分子时,体系的电流-电压(I-V)特性,随着水分子的数目和放置的位置不同,某些情况可能出现较大幅度的负微分电阻,而在另一些情况下却没有出现.更多还原

【Abstract】 We investigate the effects of H-2O molecule environment on the transport properties of a seven-atom carbon wire coupled to two Al(100) electrodes based on a recently developed ab initio nonequilibrium Green function formalism. Our results show that the transport properties are sensitive to the variation of the number and the position of the H-2O molecule on the carbon wire. Especially, the equilibrium conductance of the carbon wire with single H-2O molecule exhibits an oscillatory behavior with the shift of positions of the H-2O molecule. For the case of two H-2O molecules, the contribution of the third eigenchannel becomes larger in some configurations. The calculated current-voltage curves show different behaviors with the variation of the positions of the H-2O molecules. In certain cases, large negative differential resistance is found, but not in other cases.更多还原