Fundamental Experimental Properties of Mesoscopic Systems

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9730577 Webb This is a condensed matter physics project that investigates the quantum mechanical properties of electron transport through submicron conductors. In these very small structures the phase of the wavelength of the electron wave function are important variables that are probed by a variety of subtle experimental arrangements. The project will systematically explore the phase coherent transport properties of mesoscopic system on time scales much shorter and much longer than the phase coherence time. State- of-the-art dc superconducting quantum interference devices (SQUIDs) will be used to study the size dependence of the magnetic response of both single and arrays of metal rings. The object is an understanding of why the persistent current in phase coherent loops appears to have quantum fluctuations which are orders of magnitude larger than expected. In addition, magnetic and transport properties of mesoscopic systems whose size approaches that of the Kondo screening length will be studied. The project provides exceptional educational opportunities for graduate students and post-doctoral associates. They are involved in intellectually challenging research at the frontiers of condensed matter physics. The experiments require the latest fabrication and measurement methods and prepare the students for a wide range of scientific or technical careers. %%% This is a condensed matter physics project that employs state-of- the-art micro-fabrication methods to prepare ultra-small structures. Much of the work is focused on understanding how electrons flow through the nanoscale structures. Conventional ideas of current flow do not apply, and the wave-mechanical properties of the electron dominate the response of currents in loops, arrays of loops, films, etc. The project addresses currently unsolved problems in the quantum mechanical behav ior of the nanostructures. These problems are relevant to those involved in the microelectronics industry where the size of transistors is steadily decreasing to the so-called mesoscopic realm where quantum mechanics becomes important. An additional project deals with the properties of nano-wires containing magnetic impurity atoms. The impurities influence the electron transport in surprising and poorly understood ways. The project provides exceptional educational opportunities for graduate students and post-doctoral associates. They are involved in intellectually challenging research at the frontiers of condensed matter physics. The experiments require the latest fabrication and measurement methods and prepare the students for a wide range of scientific or technical careers. ***