Quantum Interference Controlled Molecular Electronics

Quantum interference in coherent transport through single molecular rings may provide a mechanism to control current in molecular electronics. We investigate its applicability by using a single-particle Green function method combined with ab initio electronic structure calculations. We find that the quantum interference effect (QIE) depends strongly on the interaction between molecular pi states and contact sigma states. It is absent in small molecular rings with Au leads, such as benzene, due to strong pi-sigma hybridization, while it is preserved in large rings, such as [18]annulene, which then could be used to realize QIE transistors.