Current rectification by asymmetric molecules: An ab initio study

Yan-hong Zhou; Xiao-hong Zheng; Ying Xu; Zhao Yang Zeng

doi:10.1063/1.2409689

paper

Current rectification by asymmetric molecules: An ab initio study

arXiv:cond-mat/0611508 · doi:10.1063/1.2409689

Abstract

We study current rectification effect in an asymmetric molecule HOOC-C $_{6}$ H $_{4}$ -(CH $_{2}$ ) $_{n}$ sandwiched between two Aluminum electrodes using an {\sl ab initio} nonequilibrium Green function method. The conductance of the system decreases exponentially with the increasing number $n$ of CH $_{2}$ . The phenomenon of current rectification is observed such that a very small current appears at negative bias and a sharp negative differential resistance at a critical positive bias when $n \geq 2$ . The rectification effect arises from the asymmetric structure of the molecule and the molecule-electrode couplings. A significant rectification ratio of $\sim$ 38 can be achieved when $n = 5$ .

to appear in J. Chem. Phys

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Transition from tunneling to direct contact in tungsten nanojunctions