Normal State vs. Superconductor
In recent years, there has been a tremendous expansion in the knowledge of the classes of materials which exhibit what is generally called ''metallic behavior'' and in the subclasses of these which exhibit superconductivity. In fact, it is not a trivial matter to define what constitutes a ''metal'', given that a number of organic compounds with structures which contain various low-dimension features, doped C{sub 60} fullerenes, a wide variety of intermetallic compounds, many ceramic oxides, and even suitably-doped liquid ammonia, are now considered to be metallic in character and even normally gaseous elements such as iodine and hydrogen have been made to become metallic at high pressures. A working definition of ''metallic behavior'' is that the electrical resistivity (or at least one element of the resistivity tensor in anisotropic materials) remains finite, or falls to zero in the case of superconductors, as the temperature approaches absolute zero. At the turn of the twentieth century the behavior of ''good metals'', such as Cu, Ag, Al, etc., began to be explained in terms of the behavior of independent, non-interacting ''free'' electrons by Drude and Lorentz, although these pioneering efforts were hampered by the necessity of using classical Boltzmann statistics. In the 1930s, the then-new quantum mechanics, and their attendant Fermic-Dirac statistics, were used with great success by Sommerfeld, Bloch, Wilson, and Brillouin to shed great illumination on what constituted semiconductors, metals, and insulators. This state of understanding was well-described in the classic work of Mott and Jones, ''The Theory of the Properties of Metals and Alloys'', originally published in 1936, is still in print, and is still well worth consulting even today for a cogent introduction to the normal-state properties of simple metals, transition metals and their alloys.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research (ER) (US)
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 770803
- Report Number(s):
- BNL-66982; R&D Project: KC-02-01-03; AS-012-MSD; TRN: US200509%%220
- Resource Relation:
- Other Information: PBD: 1 Dec 1999
- Country of Publication:
- United States
- Language:
- English
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