title: Current rectification by asymmetric molecules: an ab initio study.
abstract: Current rectification effect in an asymmetric molecule HCOO-C6H4-(CH2)n sandwiched between two aluminum electrodes has been studied using an ab initio nonequilibrium Green's function method. The conductance of the system decreases exponentially with the increasing number n of CH2. 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>or=2. The rectification effect arises from the asymmetric structure of the molecule and the molecule-electrode couplings. A significant rectification ratio of approximately 38 can be achieved when n=5.
authors.affiliation: Department of Physics, Jangxi Normal University, Nanchang 330022, China.
authors.forename: Yan-hong
authors.initials: YH
authors.lastname: Zhou
authors.forename: Xiao-hong
authors.initials: XH
authors.lastname: Zheng
authors.forename: Ying
authors.initials: Y
authors.lastname: Xu
authors.forename: Zhao Yang
authors.initials: ZY
authors.lastname: Zeng