DMREF: Exploring multi-functional molecular electronic materials

With this award, the Designing Materials to Revolutionize and Engineer our Future (DMREF) Program of the Division of Chemistry and the Division of Materials Research is funding Professors Hai-Ping Cheng, George Christou, and Xiaoguang Zhang at the University of Florida to study how to make magnetic materials with some of the smallest dimensions possible. Magnetic materials are important for the electronics industry and the ongoing trend towards miniaturization of devices, has made the development of ever-smaller magnets essential. The team is studying what are termed single-molecule magnets; these are individual molecules that function as magnets yet are smaller than those of traditional magnetic materials. The team is using advanced computational methods to predict which structures will yield the optimal magnetic properties and they are also studying ways to attach the single-molecule magnets to a surface to introduce certain effects crucial to the potential use of these materials in new technologies. The project is providing multi-disciplinary training to the participating graduate students and postdoctoral researchers, research opportunities for high school students through the University of Florida's Summer Student Training Program, and outreach to the general public through the including 'Chemistry Day at the Mall' activity.

The team led by Professor Cheng has demonstrated from first-principles calculations that the quantum capacitance of a small molecule or nanocluster depends upon its magnetic or geometric configuration. In this project they are now focusing on synthesizing high nuclearity manganese carboxylate clusters with various ligands and correlating the structures with the self-capacitance of the clusters and the magnetic field needed for a low-spin state to a high-spin state transition. The group is using first-principles calculations to predict the effects of changing carboxylate ligands on the magnetic states of high nuclearity manganese clusters and the effects of support surfaces (e.g. boron nitride) on the magnetic and electronic properties of these clusters. The systems are being synthesized, and various scanning tunneling microscopy, spectroscopic and electrochemical studies are being used to characterize the 'charging' properties of the nanoclusters. By searching through the three basic 'genes,' the molecule/cluster, the ligands, and the supporting substrate, the group is quantifying and characterizing how different combinations impact properties, and finding the best combination that produces the largest effect and is most suitable for applications.