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December 20, 2007

Superconductivity without phonons

The idea of superconductivity without the mediating role of lattice vibrations (phonons) has a long history.

According to researchers Pines, Monthoux and Lonzarich, electron attraction leading to superconductivity can occur without phonons in materials that are on the verge of exhibiting magnetic order—in which electrons align themselves in a regular pattern of alternating spins.

Pines, Monthoux and Lonzarich examine the material characteristics that make possible a large effective attraction that originates in the coupling of a given electron to the internal magnetic fields produced by the other electrons in the material. The resulting magnetic electron pairing can give rise to superconductivity, sometimes at substantially higher temperatures than are found in the materials for which phonons provide the pairing glue.

“If we ever find a material that superconducts at room temperature—the ‘Holy Grail’ of superconductivity—it will be within this class of materials,” says Pines. “This research shows you the lamp post under which to look for new classes of superconducting materials.”

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