Scientists come a step closer to unraveling mystery of "Holy Grail" of physics
10 Jul 2008, 1546 Hrs

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Washington, July 10 (ANI): Scientists at the University of Cambridge in the UK have for the first time identified a key component to unraveling the mystery of room temperature superconductivity, which is considered as the "Holy Grail" of physics.

The quest for room temperature superconductivity has gripped physics researchers since they saw the possibility more than two decades ago.

Materials that could potentially transport electricity with zero loss (resistance) at room temperature hold vast potential.

Some of the possible applications include a magnetically levitated superfast train, efficient magnetic resonance imaging (MRI), lossless power generators, transformers, and transmission lines, powerful supercomputers, etc.

Unfortunately, scientists have been unable to decipher how copper oxide materials superconduct at extremely cold temperatures (such as that of liquid nitrogen), much less design materials that can superconduct at higher temperatures.

Materials that are known to superconduct at the highest temperatures are, unexpectedly, ceramic insulators that behave as magnets before 'doping' (the method of introducing impurities to a semiconductor to modify its electrical properties).

Upon doping charge carriers (holes or electrons) into these parent magnetic insulators, they mysteriously begin to superconduct, i.e. the doped carriers form pairs that carry electricity without loss.

The essential conundrum facing researchers in this area has been: how does a magnet that cannot transport electricity transform into a superconductor that is a perfect conductor of electricity?

The Cambridge team has made a significant advance in answering this question.

The researchers have discovered where the charge 'hole' carriers that play a significant role in the superconductivity originate within the electronic structure of copper-oxide superconductors.

These findings are particularly important for the next step of deciphering the glue that binds the holes together and determining what enables them to superconduct.

"A major advance has been our use of high magnetic fields, which punch holes through the superconducting shroud, known as vortices - regions where superconductivity is destroyed, through which the underlying electronic structure can be probed," said Dr Suchitra E. Sebastian, lead author of the study.

"We have successfully unearthed for the first time in a high temperature superconductor the location in the electronic structure where 'pockets' of doped hole carriers aggregate," according to Sebastian.

"Our experiments have thus made an important advance toward understanding how superconducting pairs form out of these hole pockets," she added. (ANI)