Superconductivity and Nonequilibrium Transport in Mesoscopic Metals

Michigan State University, East Lansing MI

Investigators

Abstract

0104178 Birge This individual investigator award funds research in electron physics in mesoscopic metallic wires. It exploits microfabrication tools to study processes in solids that occur on submicron length scales. Four topics form the focus of the research; 1) the dephasing and energy exchange between electrons in small metallic wires below 1K; 2) spin-polarized transport in hybrid magnetic/non-magnetic systems; 3) electron transport in superconductor/non-superconductor (normal and magnetic) structures; and 4) growth of and electron transport in self-assembled rare-earth silicide nanowires. In each case the planned experiments are aimed at increasing our understanding of observed phenomena, as well as searching for potential device applications. The graduate students and post-docs working on all four of these projects learn a wide variety of technical skills associated with microfabrication. Their research experience prepares them for jobs in academia, national labs, or industry. %%% A vast array of microfabrication tools has been developed to enable the semiconductor industry to fabricate integrated circuits with millions of transistors on a single chip. Those same tools allow researchers to study the behavior of metals on length scales well below one micrometer, where many new strange phenomena occur. For example, electrons in macroscopic metals at room temperature behave essentially like tennis balls, i.e. they obey the rules of classical physics. In contrast, electrons in sub-micrometer samples at low temperature behave more like waves, i.e. they obey the rules of quantum mechanics. This leads to many interesting properties, such as the fact that some metals become superconducting at low temperature, others are magnetic, and still others remain normal metals. When different kinds of metals are put together, such as superconductors and normal metals, or ferromagnetic and nonmagnetic metals, new things happen. This individual investigator award will fund research into the properties of such very small samples in order to unravel the sometimes-mysterious new behavior, as well as to search for possible new kinds of useful devices. Students and post-doctoral research associates working in this area become familiar with the microfabrication tools used in industry, and they also learn how to think about the physics of very small devices. Former students and post-docs from this research program now work in industry, government labs, and academia. ***