Halide Anchors for Single-Cluster Electronics

Due to their unique electronic structure, well-defined metal clusters at the atomic level are promising materials for single-cluster electronics. However, coupling between the electrode and the cluster remains challenging mainly due to the coverage of bulky ligands on the noble clusters. Using the scanning tunneling microscopy break junction (STM-BJ) technique, we have developed a "direct contact" approach to fabrication and investigation of the charge transport through single-cluster junctions of AgCu bimetallic metal clusters with different halide anchors. Wefound that the electrodes could make contact directly with the surface halides of the single-cluster junctions and experience different contact resistance from different halogen atoms. Experiments and calculations reveal that the halide anchors provided efficient coupling between the cluster and the electrode, and the enhanced coupling with various halide anchors promoted electron transport and improved transmission probability. Our work offers a "direct contact" strategy for interface design between clusters of noble metals and electrodes, an essential step in progress toward single-cluster electronics.