Ab initio RTM/NEGF study on electron transport through single molecules

Using ab initio RTM/NEGF method, we study the electronic states and transport properties of single molecules sandwiched between electrodes. We find that similar non-linear I - V characteristics appear when the atomic-scale contacts are both good and bad cases. When the contact is good, molecular states are observed as peak structures in the differential conductance. On the other hand, when the contact is bad, the transport behaviors are mostly determined by the potential barrier between the single molecules and electrodes. We also find that the negative differential resistance (NDR) appears when the atomic-scale contact is close to formed. This anomalous electron transport may be utilized as a criterion for the atomic-scale contact formation. (c) 2007 Elsevier B.V. All rights reserved.