Scientific Breakthroughs

Bismuth Superconductor Begs To Differ With Conventional Superconductor Theories

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Bismuth superconductor
PHOTOGRAPH: H. Zell | Screen cap from Wikimedia Commons.

The all new bismuth superconductor is set to spoil the party of BCS Theory of Superconductivity. This is a tantalizing proposition and a subsequent breakthrough.

Funny how times can shake the order of things at the very foundations. Theories governing certain objects can lose grounds decades after their inception and pose questions. Questions that not only contradict the pre-existing theories but also ridicule them quaintly. Besides, how wrong could a Nobel-winning theory such as BCS Theory of Superconductivity be? Come bismuth superconductor – incorrect – turns out!

Bismuth As Superconductor

At extremely low temperatures, pure Bismuth carries superconductor properties, it seems. Physicists from India’s Tata Institute of Fundamental Research [TIFR] have reportedly found such a behavior in bismuth, much to their own disbelief. Upon its emergence, the latest discovery topples the equations of superconductivity tracing back to four decades ago. Notable among those – BCS Theory of Superconductivity.

A theory with condensation of Cooper pairs as the cornerstone, BCS Theory is agreeable, for the most part. A research spearheaded by Srinivasan Ramakrishnan find bismuth exhibiting superconductor properties below 0.00053 kelvin. Also, bismuth’s superconductor properties are way more than anyone could have hoped for.

As Srinivasan puts it, “people have been searching for superconductivity in bismuth for 50 years.” Without much success, however. Previously, the closest anyone got was to find that bismuth is unable to superconduct down to 0.1 kelvin. A resolute Srinivasan didn’t quit, and now he’s reaping the fruit of his labor. An odd, but intriguing property of bismuth was all it took to get Srinivasan’s undeterred attention.

In order to conduct electricity, the atoms of a substance should possess mobile electrons. Upon cooling, these mobile electrons form pairs and necessitate the flow of current. In the case of bismuth, however, there is only one mobile electron for 100,000 atoms. Perhaps, that got Srinivasan invested in his pursuit.

Superconductors in a Nutshell

First things first, superconductors are simply the substances that conduct electricity without offering resistance to flow. In other words, a current at one end of a superconductor can emerge out of the other end – minus the loss. Since its initial discovery in 1911, it has constantly given scientists a thinking point.

Over the course of the 20th century, many superconductors came into existence. Be it mercury or vanadium, they find themselves in many applications. Among all those that exhibit superconductivity, bismuth’s ways are mysterious indeed. For a substance with poor carrier density, bismuth is an aberration in itself.

In the wake of its discovery, research fraternity is gearing up for a new class of bismuth-esque low-carrier-density superconductors. Bismuth superconductors might just be for starters!

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