Advances and challenges in single-molecule electron transport

Single-molecule junctions spanning nanosized gaps between metallic contacts represent an opportunity to study electron transport on atomic length scales through specific molecular species. This review provides a critical account of key results on molecules located in break junctions or manipulated into position with scanning probe techniques. Detailed conductance measurements show a qualitative picture of the physical mechanisms for transport with the recognition that studies of benchmark systems with use of atomic scale parameters for simulation inputs will provide better quantitative agreement of theory with experiment.