Current Rectification Induced by Asymmetrical Electrode Materials in C_(20) Molecular Devices

By using first-principles method,which combines density functional theory with non-equilibrium Green's function,molecular device are constructed based on C20 connected into both electrodes with different metal materials.We investigate the effect of different electrode materials on the electronic transport properties of molecular devices.The results show that,the degrees of coupling between the molecule and electrodes are different when the devices are constructed with asymmetrical electrode materials;thus the current rectification is created.On the contrary,the rectification phenomenon disappears when the devices are constructed with symmetrical electrode materials.This rectification is fully rationalized by the variation of calculated transmission spectra and the spatial distribution of the molecular orbitals within the bias windows.This will provide an important theoretical support for the fabrication of molecular rectifier.