Density Functional Study of the I-V Characteristicsof the Ethane-dithiol (C2H4S2) Nano-Molecular Wire

We report a first-principles study of electrical transport in a singlemolecular conductor consisting of a ethane-dithiol (C2H4S2) sandwichedbetween two Au (100) electrodes. We show that the current was increased byincreasing of the external voltage biases. The projected density of states(PDOS) and transmission coefficients (T(E)) under various external voltagebiases are analyzed, and it suggests that the variation of the coupling betweenthe molecule and the electrodes with external bias leads to the increase of thecurrent. Therefore, we propose that the most origin of electron transportmechanism in molecular devices is caused by the characteristics of both themolecule and the electrodes as well as their cooperation.Furthermore, the transport properties of the buthane-dithiol (C4H6S2)molecular wire is investigated, too. The results show that the buthane-dithiolmolecular wire has a lower conductivity than the ethane-dithiol ones at variousexternal biases thus, it is a better insulator device for the molecular electronicstechnology

Keywords:

Molecular electronics , DFT , Electron transport , Non-Equilibrium Green s function , Ethane-dithiol , Buthane-dithiol. Abstract