The Emergence of Metallic Properties in Free Metal Clusters: Ground- and Metastable States

点击翻译按钮获取中文摘要

****Technical Abstract****This project studies how metallic properties develop as a function of size in clusters of atoms from a single atom to a few hundred atoms. A laser produced metal vapor cloud condenses into clusters in cryogenically cooled helium, producing a molecular beam of ultra cold clusters that are deflected in static and oscillating electric and magnetic fields. From their response the electronic properties of these clusters, in the ground state and in excited states, will be determined, revealing the evolution of superconductivity, the Kondo effect, metal conductivity and ferromagnetism is as a function of atomically precise size and composition. The understanding of these metallic properties on the nanoscale is vital for nanoscience and nanotechnologhy. The research provides undergraduate and graduate students with an exquisite opportunity to be active in frontier science while learning a wide variety of experimental techniques. ****Non-Technical Abstract****Many properties of metals, why and how some are magnetic, how they conduct electricity, and what makes some become superconductors at low temperatures are reasonably well understood in bulk samples. But single atoms of these metal have none of these properties. This project will reveal how these bulk metal properties evolve from atomic properties in clusters of metal atoms. A unique apparatus has been developed that can produce these metal clusters in high vacuum and measure them one at a time to determine how they respond to magnetic and electric fields. By measuring the forces that these fields exert on the clusters with precise knowledge of their size and composition, the evolution of metal properties can be determined. This knowledge is vital for fundamental science as well as for nanotechnology. The research also provides undergraduate and graduate students with an excellent opportunity to be active in frontier science while learning a wide variety of experimental techniques.