Current rectification by asymmetric molecules: an ab initio study.
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.
Zhou
Yan-hong
YH
Department of Physics, Jangxi Normal University, Nanchang 330022, China.
Zheng
Xiao-hong
XH
Xu
Ying
Y
Zeng
Zhao Yang
ZY