An ab initio study on the transport characteristics of Si 2 C 2 clusters

We have studied the transport properties of three different contact structures in Si 2 C 2 clusters by using the first-principles based on density functional theory (DFT) and non-equilibrium Green’s function (NEGF) in this paper. Both M1 and M2 show excellent transport properties and appear a weak NDR phenomenon due to more transferring charge between the central area and the electrodes. The intermediate barrier of M3 is very large, and the electrons are difficult to transmit. But it also shows good conductivity after we add sulfur(S) atoms at both ends of the molecule. Through the analysis of MPSH, the molecular orbital is expanded with the addition of S atoms, so it shows good conductivity. With the adding of the bias, the conductance of Si 2 C 2 clusters at the Fermi level is reduced due to the drift of the energy level. It is interesting to note that there is a high resonant transmission peak at -1.14eV under 2V bias of the M3 system, which shows a molecular switc...