• LK-99 is likely not a room-temperature superconductor.
• Replication attempts have not produced sufficient results.
• Scientists claim levitation could be from diamagnetism.

The verdict is in: LK-99 is not the beginning of a new era of electronics.

Hopes for the potential room-temperature superconductor were dashed by a scathing summary from the University of Maryland’s Condensed Matter Theory Center last week on X, formerly Twitter.

“With a great deal of sadness, we now believe that the game is over,” the tweet read.

“LK99 is NOT a superconductor, not even at room temperatures (or at very low temperatures). It is a very highly resistive poor quality material. Period. No point in fighting with the truth. Data have spoken.”

The experts drew their conclusion from the results of a growing body of replication attempts that have taken place at institutions around the world. As soon as the two original papers which debuted LK-99 were published and made the inflated claim that the result “opens a new era for humankind”, academics and amateur scientists were hot on their tracks trying to recreate it.

This enthusiasm, both from the original South Korean authors and the wider scientific community, stems from the fact that a room-temperature superconductor would revolutionize technology as we know it.

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Tech revolution from superconductors on horizon?

A superconductor is a material with zero electrical resistance, so it can conduct electricity with 100 percent efficiency. These do already exist, however, they only exhibit this property when cooled to extremely low temperatures or under extremely high pressures. This makes them very expensive to use practically for, say, wires in electricity grids which do not lose any of the electrical energy they carry as heat.

But if superconductors could be formed at room temperature, or close to it, they could be used in ultrafast and energy-efficient computer chips and servers. They would also lower the price of quantum computers, making them more widely available to solve complex problems for researchers.

LK-99 fits the bill, kind of. The researchers claimed it had zero resistance at temperatures of up to 400 K (127 °C, 260 °F) at ambient pressure. They also published a video showing it partially levitating, which they claimed was evidence of the Meissner effect, another hallmark of superconductivity.

This is when a superconductor ‘levitates’ after being placed on top of a magnet because it expels a magnetic field from its interior. The researchers added that it was not completely levitating in their video because it is an impure sample.

‘Levitating’ room-temperature semiconductor. Source: Lee S et al. (2023)

However, scientists had a problem with many of their claims. The synthesis of LK-99 involved mixing several compounds containing lead, copper, oxygen, sulfur, and phosphorus and heating them to very high temperatures, but the chemical equations provided to illustrate what was happening were not balanced. The synthetic instructions were also strangely vague, not including details like cooling rates for the furnaces.

The compound created was, as admitted by the Korean scientists themselves, not a pure sample, which negated the measurement of zero resistance. The levitation could also have been through magnetic repulsion unrelated to superconductivity.

Other common tests that confirm superconductivity were not included, and the researchers did not analyze the sample in the traditional manner which would verify its exact structure.

Finally, the accompanying video doesn’t actually show the material fully levitating – only one side rises off the magnet. This led researchers to believe that the observed Meissner effect stemmed from impurities creating areas of superconductivity rather than the compound as a whole.

The two papers themselves were submitted in an unconventional manner, with a few hours between them and attributions to different authors. Some of the researchers involved later admitted that one of the papers was incomplete and contained “many defects”.

However, there was only one way for the skeptics to be totally sure that LK-99 was a fraud – to make it themselves.

The Beihang University in Beijing quickly ruled the material as not being superconductive after their reproduced sample gave a high measurement for resistivity at room temperature and did not repel or levitate over a magnet.

This was not the case for another fragment of reproduced LK-99 from the Huazhong University of Science and Technology in China, whose video showed a fragment floating at multiple angles. This is evidence of ‘perfect diamagnetism’, an indicator of superconductivity.

First claimed successful replication of LK-99

Accomplished by a team at the Huazhong University of Science and Technology and posted 30 minutes ago.

Why this is evidence:
The LK-99 flake slightly levitates for both orientations of the magnetic field, meaning it is not simply a… pic.twitter.com/bh0x9oqaz2

— Andrew Côté (@Andercot) August 1, 2023

However, as author Chang Haixin told TIME, it is difficult to distinguish perfect diamagnetism from strong diamagnetism, and the latter is demonstrated in materials that are not superconducting. The National Taiwan University and the National Physical Laboratory of India also reported diamagnetism in their respective samples, but these did not show zero resistance or any other indication of superconductivity.

The International Center for Quantum Materials in China observed signs of ferromagnetism – where it can become magnetized by a magnetic field – in flakes of reproduced LK-99, but, again, this was ruled as not being indicative of a room-temperature superconductor.

In the fortnight since the first papers were released, and gained widespread attention through a post on Hacker News, reports from the US, Russia, Spain, and the UK have also concluded that LK-99 is not the Holy Grail material and confirmed its structure.

Andrew McCalip, an engineer at space start-up Varda Space Industries, live-streamed his ‘backyard’ replication attempt on Twitch and live-tweeted it on X. Only a few of his fragments responded to a magnetic field, and he also detected impurities that could explain the observed phenomenon.

Meissner effect or bust: Day 8.5

We made the rocks pic.twitter.com/ygVOATBaHD

— Andrew McCalip (@andrewmccalip) August 4, 2023

Other labs have provided theoretical explanations for what the South Korean team observed in their sample. Still, these do not prove that the cause is superconductivity beyond a shadow of a doubt. There have been no complete successes so far in replicated experiments.

Last week, the Korean Society of Superconductivity and Cryogenics, which set up an investigative committee at the start of August to verify the results of the original papers, told Bloomberg that it is still awaiting the original samples of LK-99 for independent assessment.

While this final result is still weeks away, the consensus is clear, albeit disappointing. Data have indeed spoken.

The post “The game is over” for room-temperature superconductivity claim appeared first on TechHQ.

• Korean researchers claim room temperature superconductor discovery
• Superconductors have zero electrical resistance so are highly efficient
• If verified, applications include power grids, computing, and quantum tech

Just over a week ago, scientists and science enthusiasts around the world were sent into a state of shock, excitement, and tentative cynicism after a group of researchers from South Korea made an extraordinary claim: that they had created the world’s first room-temperature superconductor.

Superconductors are materials that can conduct electricity with zero resistance. In ordinary conductors, like copper wires, some energy is lost as heat when electricity flows through them as electrons collide with and repel each other.

But in superconductors, this loss of energy is completely eliminated. This makes them incredibly efficient conductors of electricity, meaning they can carry large amounts of electricity without generating wasteful heat or losing energy along the way.

Maglev trains float above the tracks using powerful superconductors, eliminating friction for high-speed travel. Source: Shutterstock

Why a ‘room-temperature’ superconductor?

Most superconducting materials must be at a very low temperature, often close to absolute zero (-459°F, -273°C), or very high pressure (more than 100,000 times atmospheric pressure) to exhibit superconductivity. This is because, in these extreme conditions, the electrons in the material pair up and form what’s known as Cooper pairs.

Since they are bound together, these pairs avoid scattering with each other and the lattice ions that would typically cause energy loss and resistance in a regular conductor. Therefore they can flow the material with zero resistance until the temperature is raised or pressure is lowered and they are disrupted.

Researchers have been working tirelessly to find materials or mechanisms that can maintain Cooper pairs at higher temperatures and lower pressures, but it is not easy. The intricate balance of interactions among the atoms and electrons in the target material must be precisely controlled to achieve the necessary stability under ambient conditions.

The current requirements for harnessing a superconductor mean they are expensive to make use of practically. However, they are used in critical applications where their unique properties outweigh the cost considerations, including particle accelerators and MRI machines.

MRI machines utilize superconducting magnets to create a strong magnetic field for detailed medical imaging.  Source: Shutterstock

Over the years, a few different research teams have claimed to have discovered the ‘Holy Grail’ material that superconducts under ambient conditions, but they have never stood up under scrutiny, with papers being retracted and results proving unreplicable.

However, on July 22, a Korean team published two preprint papers on arXiv claiming that their new material, LK-99, “opens a new era for humankind”. They created LK-99 by mixing several compounds containing lead, oxygen, sulfur, and phosphorus and subjecting them to extreme heat for several hours.

This turned the powder into a dark grey solid which apparently exhibits zero resistance at temperatures less than 261°F (127°C) and at atmospheric pressure. Its superconductivity is also said to be proven by something called the Meissner effect, where the material expels a magnetic field from its interior. This causes the superconductor to levitate when placed above a magnet, and LK-99 was filmed partially doing so in a now-viral video.

Most of the time, demonstrating this effect is accompanied by cooling the material with liquid nitrogen so it becomes a superconductor, but for LK-99 this was not necessary.

However, these results have been met with speculation from other scientists. For one thing, in the video, only part of the LK-99 sample levitates over the magnet while the other edge remains in contact.

Some say that this effect could be due to impurities in the sample creating areas of superconductivity and is therefore not evidence that the material as a whole has the property. The researchers behind LK-99 also have not provided definitive experimental evidence to support their theory of how it exhibits room-temperature superconductivity.

The basic synthesis for LK-99 outlined in the paper, which doesn’t involve equipment any more complex than an oven and a pestle and mortar, has led kitchen scientists to try and replicate the experiment themselves, as well as experienced academics. So far, all of these have resulted in inconclusive results or outright failures.

One of my tangential takeaways on this LK-99 SC claim is that the general public seems oddly pumped about how “easy” the 4-day, multi-step, small batch, solid state synthesis is. Some of you haven’t had blisters from overusing your pestle and it shows.

— Jennifer Fowlie (@jennifer_fowlie) July 26, 2023

Quantum computing made cheap?

But why do we care about LK-99? What would a room-temperature superconductor actually mean for our tech?

Well, quite a lot. Materials that are superconductive under standard conditions would revolutionize electricity grids. According to estimates made by Massoud Pedram, an electrical engineering professor at the University of Southern California, our grids would be about 20 percent more efficient with superconducting wires.

An enormous amount of energy – approximately 949 million metric tons of carbon dioxide equivalents – is wasted every year due to electrical resistance in power lines. The lack of resistance would be beneficial to the global economy and environment.

‘High-temperature’ superconductors have been installed periodically in the past. For example, in 2021, Nexans used one to connect electricity grid substations in Chicago to help prevent power outages. Despite the name, they must be kept at about -328°F (-200°C) with a cryogenic jacket filled with liquid nitrogen, making them impractical for widespread adoption.

Nexans’ high-temperature superconducting cables offer efficient power transmission. Source: Nexans

But according to the US Department of Energy, even these high-temperature superconducting wires would save the US alone hundreds of billions of dollars annually in energy distribution costs.

But it’s not just electricity grids that a room-temperature superconductor would improve, as the humble PC would get a transformation too. Next-generation computers would benefit from ultra-high-speed digital interconnects and low-latency broadband wireless communications. They would also run on ultrafast and energy-efficient computer chips, leading to significantly faster processing speeds while consuming orders of magnitude less power.

Servers in data centers would experience a similar uptick in speed thanks to minimized resistance and energy loss in the computing components. As a result, businesses heavily reliant on data centers for their operations would experience increased efficiency and cost savings.

Many quantum computing experiments currently rely on high-temperature superconductors to manipulate and store qubits. Source: Shutterstock

Many quantum computing experiments currently rely on high-temperature superconductors to manipulate and store qubits. A qubit, short for quantum bit, is the fundamental unit of quantum information and forms the building block of quantum computers.

Unlike classical bits, which can represent either 0 or 1, qubits can exist simultaneously in a superposition of both states, enabling quantum computers to perform complex parallel computations.

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Superconductors are essential for qubits because they exhibit zero electrical resistance and high coherence, allowing them to maintain their delicate quantum states without any disruption from external influences or energy loss. With room-temperature superconductors, there would no longer be a need to encase these qubits in costly and complex cryogenic cooling systems.

They would make quantum computers more practical, easier to scale, and open up new possibilities for solving complex problems with unprecedented computational power in multiple industries.

Other enterprise technologies that would receive a boost in efficiency from room-temperature superconductors include telecommunications infrastructure and IoT devices, while sensors, like those used in medicine, manufacturing, and aerospace, would experience increased sensitivity.

The papers from the South Korean researchers are now going through peer review, so time will tell whether their discovery is as ground-breaking as hoped.

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