Activated Conduction in Microscopic Molecular Junctions
Activated Conduction in Microscopic Molecular Junctions
复制标题
微观分子连接中的激活传导
DOI：
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发表时间：
2000
期刊：
影响因子：
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通讯作者：
W. B. Davis
中科院分区：
文献类型：
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作者：
D. Segal;A. Nitzan;M. Ratner;W. B. Davis
我们分析了通过给定分子桥的电子转移速率与基于同一分子桥的两个金属之间的结传导之间的关系。将结的传导率与其传输性能之间的朗道尔关系推广到传导率与ET速率之间的关系，包括热活化主导的传递过程。这些可观测值的数量级之间的关系涉及到一个附加的长度参数，即供体波函数范围的数量级。我们发现，随着N的增加，这些观测值对桥长(N)和温度(T)的函数依赖关系从指数和温度无关的exp（−βN）转变为代数和热激活的形式(α1 + α2N)-1 exp（−ΔE/kBT）。如果α1比α2强，则存在一个与N无关的中间范围。这种行为类似于量子克雷默斯（障垒穿越）问题，并对其进行了分析。
We analyze the connection between the electron transfer (ET) rate through a given molecular bridge, and the conduction of a junction based on the same bridge between two metals. The Landauer relation between the conduction of a junction and its transmission properties is generalized to yield a relation between conduction and ET rate, including transfer processes dominated by thermal activation. The relation between the orders of magnitude of these observables involves an additional length parameter, of the order of the range of the donor wave function. We find that the functional dependence of these observables on the bridge length (N) and on the temperature (T) changes from the exponential and temperature independent, exp(−βN) for small N, to algebraic and thermally activated form, (α1 + α2N)-1 exp(−ΔE/kBT), as N increases. An intermediate range of apparent independence on N exists if α1 ≫ α2. This behavior is the analogue to the quantum Kramers (barrier crossing) problem, analyzed with respect to the ba...