Periodic trends in electron transport through extended metal atom chains: comparison of Ru3(dpa)4(NCS)2 with its first-row analogues
Periodic trends in electron transport through extended metal atom chains: comparison of Ru3(dpa)4(NCS)2 with its first-row analogues
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DOI：
10.1039/c2sc01024k
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发表时间：
2012-03
期刊：
影响因子：
8.4
通讯作者：
P. Mohan;V. Georgiev;J. McGrady
中科院分区：
文献类型：
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作者：
P. Mohan;V. Georgiev;J. McGrady
密度泛函理论被用来调和的结构，磁性和电子输运性质的三钌扩展的金属原子链，Ru 3（dpa）4（NCS）2。在这个物种中，Ru-Ru-Ru核的明显弯曲可以追溯到在线性几何中接近简并的σ和π对称性水平之间的强二阶混合。主要的电子传输通道由LUMO形成，LUMO是位于金电极的费米能级之上的π* 对称轨道。弯曲对电子输运有重大影响，因为它会诱导从五重态到单重态的自旋交叉，这反过来又使LUMO更接近费米能级。金属链中显著的净π键合的存在也加宽了π/πnb/π* 流形，使得即使在1.0 V的偏压下，通道也不会受到电场的强烈扰动。稳健的π对称传导通道的存在标志着三钌系统与其第一行对应物Cr 3（dpa）4（NCS）2和Co 3（dpa）4（NCS）2完全不同，其中电流主要通过σ框架流动。
Density functional theory is used to reconcile the structural, magnetic and electron transport properties of a triruthenium extended metal atom chain, Ru3(dpa)4(NCS)2. The distinct bending of the Ru–Ru–Ru core in this species is traced to strong second-order mixing between levels of σ and π symmetry that are near degenerate in the linear geometry. The dominant electron transport channel is formed by the LUMO, an orbital of π* symmetry that lies just above the Fermi level of the gold electrode. The bending has a substantial impact on electron transport in that it induces a spin crossover from a quintet to a singlet which in turn brings the LUMO much closer to the Fermi level. The presence of significant net π bonding in the metal chains also broadens the π/πnb/π* manifold, such that the channel is not strongly perturbed by the electric field, even at a bias of 1.0 V. The presence of a robust π symmetry conduction channel marks the triruthenium systems out as quite distinct from its first-row counterparts, Cr3(dpa)4(NCS)2 and Co3(dpa)4(NCS)2, where current flows primarily through the σ framework.