Electronic Structure and Superconductivity in NAxCoO2 YH2O
NAVAL RESEARCH LAB WASHINGTON DC MATERIAL SCIENCE AND TECHNOLOGY DIV
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The Navy has long had an interest in developing a superconducting homopolar motor for ship propulsion. A giant step toward practical implementation came with the discovery of high critical temperature, or high Tc, superconductors. These are compounds capable of carrying a resistanceless current at temperatures above that of liquid nitrogen. The performance of these motors depends sensitively on the ability to create and stabilize a large current density. Therefore, detailed understanding of the microstructure and underlying physics of superconducting materials is crucial to further technological development. The experimental breakthrough of synthesizing high Tc compounds was accompanied by the realization that well-established theories explaining the microscopic origins of superconductivity could not adequately explain these new materials. The search for a coherent and complete description of unconventional superconductivity as a step toward development of even better devices and applications is therefore a primary concern of materials science theory. Superconductivity is an intrinsically quantum mechanical phenomenon arising from pairing between electrons. Since each electron individually has its own quantum properties, the paired-state characteristics depend on the detailed properties of unpaired electrons in the normal metallic state. An instability of the Fermi surfaces of this normal state causes condensation into a superconducting fluid of electron pairs. From an understanding of Fermi surface geometry, many properties of the superconducting state can be deduced.
- Inorganic Chemistry
- Electricity and Magnetism