This project will pursue experiments to significantly advance the understanding of the origin of superconductivity in the high-Tc cuprate superconductors and the pairing symmetry of iron-based superconductors. The goal is to study and understand the low-temperature normal state properties of the electron-doped high-Tc superconductors and to use this new knowledge to impact the understanding of all the cuprates, hole- and electron-doped. The electron-doped cuprate research will be carried out via a variety of transport experiments in ambient magnetic field and in fields above the upper critical field down to milliKelvin temperatures. Some transport experiments will be done under hydrostatic pressure or strain. The iron-based superconductor research will be attempted via phase-sensitive Josephson tunneling experiments in a SQUID or corner junction arrangement, as proposed in several theoretical papers. An important goal of all these experiments is to understand the mechanism of superconductivity in these two classes of unconventional high-Tc materials, a major unsolved problem in condensed matter physics. A comparison of the normal state and superconducting properties of these two systems is expected to lead to new and important insights into the role of electronic correlations in high-Tc superconductors. This project will support the education of one postdoctoral fellow in the physics, materials science and measurement techniques necessary to carry out the proposed research. From past experience, this type of research has shown itself to be an excellent training for many scientific careers from academia to high technology industries.
The cause of the high-temperature superconductivity found in some copper oxide and iron-based materials is one of the most important unsolved problems in condensed matter physics. These materials have great potential for use in energy related technologies, such as improved motors and electricity generation and transmission. It is crucial to understand the mechanism of superconductivity in these materials in order to develop the knowledge to discover new superconductors that will work at room temperature and above. This project will pursue experiments designed to solve this basic scientific question, and which may also help to develop useful technology. This will be accomplished by employing advanced transport measurement techniques, novel synthetic methods for making new materials and improved thin-film versions of known materials, and by using national laboratory facilities for measurements under extreme magnetic field and temperature conditions. This project will support the education of one postdoctoral fellow in the physics, materials science and measurement techniques necessary to carry out the proposed research. From past experience, this type of research has shown itself to be an excellent training for many scientific careers from academia to high technology industries. If room temperature superconductors can be discovered they will have a significant impact on many current technologies, from energy to communication.
