Unraveling the stripe order mystery

One of the greatest mysteries in condensed matter physics is the exact relationship between charge order and superconductivity in cuprate superconductors. In superconductors, electrons move freely through the material—there ...

New material shows high potential for quantum computing

A joint team of scientists at the University of California, Riverside, and the Massachusetts Institute of Technology is getting closer to confirming the existence of an exotic quantum particle called Majorana fermion, crucial ...

A peculiar ground-state phase for 2-D superconductors

The application of large enough magnetic fields results in the disruption of superconducting states in materials, even at drastically low temperature, thereby changing them directly into insulators—or so was traditionally ...

New cuprate superconductor may challenge classical wisdom

Superconductivity is one of the most mysterious phenomena in nature in that materials can conduct electrical current without any resistance. Cuprates hold the record high superconducting temperature at ambient pressure so ...

Perfect quantum portal emerges at exotic interface

Researchers at the University of Maryland have captured the most direct evidence to date of a quantum quirk that allows particles to tunnel through a barrier like it's not even there. The result, featured on the cover of ...

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Superconductivity

Superconductivity is a phenomenon occurring in certain materials generally at very low temperatures, characterized by exactly zero electrical resistance and the exclusion of the interior magnetic field (the Meissner effect). It was discovered by Heike Kamerlingh Onnes in 1911. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon. It cannot be understood simply as the idealization of "perfect conductivity" in classical physics.

The electrical resistivity of a metallic conductor decreases gradually as the temperature is lowered. However, in ordinary conductors such as copper and silver, impurities and other defects impose a lower limit. Even near absolute zero a real sample of copper shows a non-zero resistance. The resistance of a superconductor, despite these imperfections, drops abruptly to zero when the material is cooled below its "critical temperature". An electric current flowing in a loop of superconducting wire can persist indefinitely with no power source.

Superconductivity occurs in a wide variety of materials, including simple elements like tin and aluminium, various metallic alloys and some heavily-doped semiconductors. Superconductivity does not occur in noble metals like gold and silver, nor in pure samples of ferromagnetic metals.

In 1986 the discovery of a family of cuprate-perovskite ceramic materials known as high-temperature superconductors, with critical temperatures in excess of 90 kelvin, spurred renewed interest and research in superconductivity for several reasons. As a topic of pure research, these materials represented a new phenomenon not explained by the current theory. In addition, because the superconducting state persists up to more manageable temperatures, past the economically-important boiling point of liquid nitrogen (77 kelvin), more commercial applications are feasible, especially if materials with even higher critical temperatures could be discovered.

See also the history of superconductivity.

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