Quantized ionic conductance in nanopores.
Quantized ionic conductance in nanopores.
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DOI：
10.1103/physrevlett.103.128102
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发表时间：
2009-09-18
影响因子：
8.6
通讯作者：
Di Ventra M
中科院分区：
文献类型：
--
作者：
Zwolak M;Lagerqvist J;Di Ventra M
鉴于其在生物过程中的存在及其对新的DNA测序应用的影响，纳米孔中的离子传输是一个从根本上和技术上重要的问题。利用微观计算，我们证明了离子输运可能表现出作为孔半径的函数的强非线性，这让人想起电导量子化步骤作为量子点接触的横截面的函数。然而，在目前的情况下，电导步骤起源于水溶液中围绕离子形成的水化层的破裂。一旦进入孔道，由于孔壁表面的多次散射和与离子周围的径向波的干扰，水分子形成了波状结构。我们讨论了这些效应以及在什么条件下离子电导中的阶梯状特征应该是实验上可以观察到的。
Ionic transport in nanopores is a fundamentally and technologically important problem in view of its occurrence in biological processes and its impact on novel DNA sequencing applications. Using microscopic calculations, here we show that ion transport may exhibit strong nonlinearities as a function of the pore radius reminiscent of the conductance quantization steps as a function of the transverse cross section of quantum point contacts. In the present case, however, conductance steps originate from the break up of the hydration layers that form around ions in aqueous solution. Once in the pore, the water molecules form wavelike structures due to multiple scattering at the surface of the pore walls and interference with the radial waves around the ion. We discuss these effects as well as the conditions under which the step-like features in the ionic conductance should be experimentally observable.