by If you haven’t heard of superconductors before 2023, it looks like you know what they are now. Researchers raised eyebrows earlier this year with claims of superconductors operating at room temperature, although none of them are substantiated, and the journal Nature retracted one paper by researchers at the University of Rochester at the request of the authors in November .
But the quest for a superconductor – that is, a material capable of conducting electricity without resistance – that can operate at room temperature is nothing new.
Currently, superconductors can only work at very cold temperatures. So finding one that could work at room temperature without needing to be kept in a cold room could revolutionize everything from power grids and medical equipment to quantum computing. But physicists must first figure out how to make them work.
A Dutch physicist discovered the phenomenon of superconductivity in the early 20th century, and since then, laboratories around the world have tested materials that can achieve a superconducting state at hotter and hotter temperatures.
So how do these materials manage to conduct electricity without resistance, and what kinds of technological possibilities are on the horizon, as superconductor research improves every year? Here are three stories from The Conversation archives that explore the history, science and future of this incredible physical phenomenon.
1. Physics behind the phenomenon
How can even generate a current with zero electrical resistance, the basis for superconductivity? To do that, you have to keep your conductive metal cold. Really cold. Like, hundreds of degrees below zero.
“At normal temperatures, electrons move in irregular paths. They can usually move freely through a string, but occasionally they collide with the nuclei of matter,” wrote Mishkat Bhattacharya, a physicist at the Rochester Institute of Technology. “These collisions are what block the flow of electrons, which add resistance and heat the material.”
Normally, the nuclei of all atoms are constantly vibrating, and they can bump into each other. In superconducting materials, the electrons flow from atom to atom vibrating at the same frequency as the nuclei of the atoms in the superconducting metal. This means that instead of colliding and generating heat, they are moving in a smooth and coordinated way. And it is the cold temperatures that allow this coordinated movement.
Read more: How do referrals work? A physicist explains what it means to have resistance-free electricity
2. A century of superconductivity
Mercury was the first material discovered as a superconductor by Heike Kamerlingh Onnes in 1911. His team had to cool liquid helium to -454 degrees Fahrenheit (-270 degrees Celsius) to observe the effect. They used mercury wires to send a current through the material, and then measured the effect of electrical resistance as “pretty much null”.
Onnes and his team repeated the experiment to ensure that the effect they observed was, indeed, superconductivity, and ruled out all other possible explanations for the effect – electrical defects, open currents and so on. But they kept finding the same result, and after three years of testing, Onnes was able to demonstrate currents with zero absolute resistance.
“Superconductivity has always been difficult to create because certain metals can masquerade as superconductors,” wrote David D. Nolte, author of the history of science books and a physicist at Purdue. “The lessons Onnes learned a century ago – that these discoveries require time, patience and, most importantly, proof of currents that never stop – are still relevant today.”
Read more: Superconductivity at room temperature remains invisible a century after Nobel went to the scientist who demonstrated it at -450 degrees Fahrenheit
3. A superconducting future
One of the most important functions of a room temperature superconductor in the future is to reduce the heat wasted from electronics. Not only could electronics like cell phones and computers run much faster and more efficiently, but on a larger scale, electrical grids, power lines and data centers could reduce their wasted heat. This could be a huge win for the environment.
“If we succeed in making a room-temperature superconductor, we can address the billions of dollars it costs in wasted heat to transmit energy from power plants to cities,” wrote Pegor Aynajian, a physicist at Binghamton University, State University New York. “Solar energy harvested in the vast empty deserts of the world could be stored and transmitted without any energy loss, potentially powering cities and dramatically reducing greenhouse gas emissions.”
A type of superconductor made from a ceramic-like material discovered by scientists at IBM in Switzerland could be one path to a room-temperature superconductor. Already, this class of material has been shown to operate at higher temperatures – although still frigid – closer to -300 F (-184 C) than conventional subconductors such as Onnes’ original mercury wires.
But while a room-temperature superconductor could revolutionize electronics and energy transmission, the right material is still elusive. As Aynajian puts it, the next million dollar question is a room temperature superconductor.
Read more: Physicists hunt for room-temperature superconductors that could revolutionize the world’s energy system
This story is a summary of articles from The Conversation archives.
This article is republished from The Conversation, a non-profit, independent news organization that brings you facts and analysis to help you make sense of our complex world.
It was written by: Mary Magnuson, The conversation.
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