Electronic Properties of Single Atom and Molecule Junctions

Single atom and molecule junctions are key components of future ultra-small electronic devices. The novel properties and functionalities appear in the single atom and molecule junctions reflecting their unique structures. The conductance quantization and quantum interface effects have been reported. In this review, we discuss fabrication and electronic properties of the single atom and molecule junctions, including electrical conductance and thermopower. The single atom and molecule junctions are fabricated in a nanogap prepared by electron migration, self-breaking and mechanical breaking of metal wires. The electric conductance of the single atom and molecule junctions depends not only the atom and molecule within the junctions, but also on their connectivity to the metal wires at the interface. The conductance fluctuation characteristic of single-molecule junction reflects the character of the metal-molecular bond at the interface, which enables us to study the molecular adsorption process during the formation of the junction.