In March, a scientific research paper claimed a “groundbreaking” discovery. The authors had apparently discovered a room-temperature superconductor, which at present almost seems an oxymoron. The paper, published in the prestigious journal Nature, had the potential for a major breakthrough for the scientific world.

Before we go further, remember that superconductors, or materials that have the property of superconductivity, are deemed the “holy grail” in the world of science. Simply put, they can, under specific conditions, conduct electric current without any resistance—this means no waste heat generated and no energy lost. More on this later. Now, coming back to the revolutionary paper.

Months after the initial buzz and hopes of a giant leap for the scientific community, the discovery went up in smoke. Nature retracted the paper on Tuesday.

The journal said it did so due to integrity concerns raised by eight of the 11 co-authors. The co-authors “expressed the view as researchers who contributed to the work that the published paper does not accurately reflect the provenance of the investigated materials, the experimental measurements undertaken and the data-processing protocols applied.”

Interestingly, this will be the third time that lead authors—physicists Ranga Dias from the University of Rochester and Ashkan Salamat from the University of Nevada—have had their high-profile papers retracted. An earlier paper, also published in Nature, and one in the journal Physical Review Letters were retracted.

More interesting is the credibility allegation against Dias. Researchers have claimed that he plagiarized portions of his PhD thesis.

This retracted paper joins the ranks of many claims of discovering room-temperature superconductors that have ultimately fallen flat. Let’s look a little deeper into superconductors to understand why scientists have desperately been trying to come up with discoveries related to it.

The material in question

Discovered in 1911, superconductors are materials that can conduct electric current without resistance. Traditional superconductors only exhibit this property at extremely low temperatures, under high pressure, or both.

So far, scientists have made progress with higher temperature superconductors—which need to be cooled to around -23 degrees Celsius (-9 degrees Fahrenheit). These temperatures are “higher” in comparison to previously known superconductors, which function at even colder temperatures—more than 250 degrees Celsius below zero, or very close to absolute zero, which is –273 degrees Celsius. These newer superconductors are easier to work with, but still require special thermal equipment and very high pressure.

However, room-temperature superconductors, unlike their counterparts, won’t need special equipment for cooling. They will still require the application of pressure, albeit at a much more achievable level—roughly 10,000 times more than atmospheric pressure.

Though the quest for near-ambient superconductors remains elusive for now, let’s take a closer look at the retracted paper.

The paper that is no more

The now-retracted paper, titled “Evidence of near-ambient superconductivity in a N-doped lutetium hydride”, reported “evidence” that a material—nitrogen-doped lutetium hydride—is capable of superconducting electricity at temperatures as high as 21°C. Note that the ideal room temperature ranges from 20-22°C. Besides favourable temperature, the paper also claimed that the material required relatively modest pressure.

While other research groups have observed superconductivity with hydrogen compounds (or hydrides) at high temperatures, they have had to exert pressure as high as hundreds of gigapascals (GPa)—roughly millions of times greater than the atmospheric pressure. In contrast, Dias’ paper claimed that the mentioned hydride needed only 1 GPa (10,000 times atmospheric pressure), still impractical for everyday use but a significant step forward.

Interestingly, the material was nicknamed “reddmatter”, a hat tip to a red substance featured in the Star Trek universe, as the material exhibited a red hue on being squeezed, according to The New York Times.

While Lilia Boeri, a physicist at the Sapienza University of Rome, had said in September that “this was potentially a Nobel Prize discovery,” Boeri and several other physicists were sceptical about the claim given Dias’ track record. In the same month, Nature added a note of caution to the paper: “Readers are alerted that the reliability of data presented in this manuscript is currently in question.”

While Tuesday’s retraction notice has not provided further details pinpointing errors in the paper, it noted that “concerns have been independently raised with the journal regarding the reliability of the electrical resistance data presented in the paper”.

“An investigation by the journal and post-publication review have concluded that these concerns are credible, substantial and remain unresolved,” the notice added.

Coming to the next question: Why are physicists chasing room-temperature superconductors?

The super quest for superconductors

Room-temperature superconductors hold the potential to revolutionize industries. The possibilities are endless, as the absence of resistance in superconductors allows them to handle high electrical currents without energy loss, making them ideal for efficient power transmission. Such ambient materials could be easily used to create ultra-efficient electricity grids, ultrafast and energy-efficient computer chips, powerful magnets and more, according to The Conversation. Most importantly, these could be cheaper in the long run and easier to manage.

The tech industry also has its eyes on the material. Room-temperature superconductors can facilitate high-speed digital interconnects for next-generation computers, faster wireless communication, advanced imaging, biomedical and security sensors, deep-space radio astrophysics and more, the report added.

With such superconductors, computers would also run faster. And quantum computers could be built with a substantially higher number of qubits, equipping them to solve problems well beyond the capabilities of the most advanced supercomputers currently. (A qubit is a fundamental unit of quantum information.)

Simply put, it could be a game changer for most sectors. And while this retraction is a setback, it is not the first.

Not the first claim

Several “discoveries” claiming that they have found room-temperature superconductors have popped up but none held up. In July, a group of South Korean physicists of the Seoul-based startup company Quantum Energy Research Center claimed that they had developed a material—called LK-99—which was a room-temperature superconductor under normal pressure.

A video showing the material levitating over a magnet went viral on social media and quickly thrust the concept of a room-temperature superconductor into the limelight. Superconductivity causes materials to basically levitate above magnets due to the Meissner effect, which “pushes” a magnetic field away from the substance.

Magical, isn’t it? Unfortunately, the joy was short-lived.

LK-99 failed to live up to the claim as labs around the world failed to carry out the experiment successfully and concluded that this material is not a superconductor.

In 2020, Nature had published another paper by Dias and his team, featuring a different hydride they deemed a superconductor, but only under extremely high pressures. Again, data in this paper raised eyebrows among other scientists. And, after an investigation, Nature decided to retract the paper in September last year, despite objections from the authors. Almost a deja vu.

Dias’ other retracted paper—published by the Physical Review Letters in 2021—taken down in August, did not discuss superconductivity directly but described electrical properties in another chemical compound—manganese sulphide.