Every few years a room-temperature superconductor is announced, markets move, and within weeks the claim collapses. It has happened often enough to look like a pattern of hype.
It is actually three different patterns, and telling them apart is the whole story. One claim was a measurement artefact. One was a research-integrity failure. And one is entirely real — it simply requires 1.7 million atmospheres of pressure, which makes it useless for anything you would want to build.
Only the third is a physics problem. The first two were failures of process, and lumping them together is what makes the field look more hopeless than it is.
Meanwhile something genuinely significant happened quietly in March 2026: a record that had stood since 1993 was broken. Not room temperature — not close — but the first real movement on that number in 33 years.
What a Superconductor Actually Does
A superconductor is a material with exactly zero electrical resistance below a certain temperature, called its critical temperature or Tc. Not very low resistance — zero. A current started in a superconducting loop will circulate indefinitely without fading.
It does a second thing too, which is what you see in the photograph above. A superconductor expels magnetic fields from its interior — the Meissner effect — and that expulsion is what holds a magnet suspended in mid-air above a cooled sample. The levitation is not a party trick bolted on; it is a direct consequence of the same state that kills the resistance.
Ordinary conductors waste energy as heat. Roughly a twentieth of all electricity generated is lost in transmission. A superconducting grid would lose none of it. That is the prize, and it is why a material that worked at everyday temperatures would be a genuine civilisational upgrade rather than merely a good product.
Why Cold Is Not a Detail
The temperature requirement is not an engineering inconvenience waiting to be optimised away. It is the mechanism.
In a normal metal, electrons collide with vibrating atoms in the crystal lattice and lose energy. That loss is resistance. Below the critical temperature, electrons instead bind into pairs that behave collectively as a single quantum entity, and those pairs move through the lattice without scattering at all.
Heat is random motion. Enough of it breaks the pairing, and the material reverts to an ordinary conductor. So raising the critical temperature means finding a material where the pairing is strong enough to survive more thermal energy — and nobody can reliably predict which materials those are. The theory that explains conventional superconductors does not explain the best ones we have found. That is why progress has come from searching rather than from design.
The Summer of LK-99
In July 2023, Sukbae Lee and Ji-Hoon Kim and colleagues posted two papers to arXiv claiming a modified lead-apatite compound, LK-99, superconducted at room temperature and ambient pressure. A video showed a fragment partially lifting off a magnet. For about six weeks it was the most discussed result in physics.
Replication attempts began within days and went badly. A team at India's CSIR-National Physical Laboratory found their sample was weakly magnetic rather than field-expelling. A Beihang University group found theirs behaved like a semiconductor. At Princeton, Leslie Schoop's team found their best crystal contained at least three distinct components — the published recipe did not produce a single-phase material at all.
The decisive experiment came on 14 August 2023, when a team at the Max Planck Institute for Solid State Research in Stuttgart grew pure single crystals of LK-99 using floating-zone crystal growth. The result was a transparent purple crystal that was not a superconductor but an insulator, with resistance in the millions of ohms.
With the pure material in hand, the original observations were explained. The synthesis had produced copper sulfide (Cu₂S) as an impurity. Cu₂S undergoes a structural change near 385 K, and across that change its resistivity falls by three to four orders of magnitude — a sharp drop that superficially resembles a superconducting transition and is nothing of the kind. The partial levitation was ferromagnetism in the same impurity.
Andrei Bernevig of Princeton summarised the episode bluntly: "A lot of the stuff early on was rushed and statements from all sides were unchecked... I hope we never do science like this again."
LK-99 is worth understanding precisely because nobody cheated. A real measurement was made, and it was misread. That is an ordinary scientific failure, and the correction worked exactly as it should — within six weeks, in public.
The Retractions That Did More Damage
The other story is not ordinary.
Between 2020 and 2023, Ranga Dias at the University of Rochester published a series of high-profile room-temperature superconductivity claims, including a March 2023 Nature paper on a lutetium-hydrogen-nitrogen compound. Nature retracted it on 7 November 2023 — the third retraction for Dias's group.
The retraction note records that eight of the paper's eleven authors, not including Dias, requested the withdrawal. Earlier that year his own graduate students, with a collaborator at UNLV, had written to Nature setting out what they believed was research misconduct. Rochester removed Dias from his laboratories and from supervising students in August 2023, and external investigators subsequently found data-reliability concerns in the retracted papers. Dias has continued to stand by the claim.
The damage here is different in kind from LK-99. A misread measurement costs a few weeks. A sustained integrity failure makes every subsequent honest result in the field harder to publish and harder to believe.
Where the Records Actually Sit
Strip out the noise and the real numbers are unglamorous but solid.
The most important line on that ladder is 77 K — the boiling point of liquid nitrogen. Below it you need liquid helium, which is expensive and increasingly scarce. Above it you can cool with liquid nitrogen, which costs less per litre than milk. Crossing 77 K in 1986–87 is what turned superconductivity from a laboratory curiosity into an industry, and it is why materials above that line are called high-temperature superconductors even though they are still colder than anywhere on Earth.
The 2026 Result That Broke a 33-Year Record
The ambient-pressure record had belonged to a mercury-based copper-oxide ceramic called Hg1223 at 133 K since 1993. In March 2026, Liangzi Deng, Ching-Wu Chu and colleagues at the University of Houston raised it to 151 K, publishing in the Proceedings of the National Academy of Sciences.
What makes the result interesting is the method rather than the number. They did not find a new material — they used the same Hg1223. Instead they applied high pressure, which is already known to raise Tc, then released it rapidly at a controlled low temperature. The material stays trapped in the compressed, higher-Tc arrangement after the pressure is gone. The technique is called pressure quenching, and if it generalises it opens a very large search space in known materials rather than requiring new ones.
Two caveats belong next to that number, and most coverage dropped them.
First, the state is metastable, not permanent. It survived at least three days stored in liquid nitrogen at 77 K, and degraded at warmer temperatures around 200 K. A superconductor you must keep cold to preserve its ability to superconduct while warm is a scientific result, not yet a technology.
Second, Houston itself says plainly that ambient-pressure room-temperature superconductivity "remains the ultimate goal." The gap from 151 K to 293 K is about 142 degrees — larger than the entire distance from absolute zero to the new record.
The Pressure Problem
The highest critical temperatures ever measured do come close to room temperature. In 2015, sulfur hydride was shown to superconduct at 203 K; in 2019, lanthanum hydride reached around 250 K.
Both required pressures near 150–200 gigapascals, which is one and a half to two million times atmospheric pressure, comparable to conditions in the Earth's outer core. These samples exist between the tips of two diamonds in a diamond anvil cell, in volumes measured in micrometres.
These are genuine superconductors and genuinely important physics — they confirmed that hydrogen-rich compounds can pair electrons strongly. They are also, as engineering, unusable. You cannot run a power line through a diamond anvil cell. This is why "we already have near-room-temperature superconductors" is technically true and practically meaningless, and why the pressure-quenching approach matters: it is an attempt to keep the physics and discard the press.
What "Warm" Superconductors Already Do
Lost in the room-temperature argument is that superconductors stopped being speculative decades ago. They are load-bearing infrastructure right now.
Superconductors in Service Today
None of these need room temperature. All of them need superconductivity.
| Where | Material and temperature | Why it has to be superconducting |
|---|---|---|
| WhereMRI scanners | Material and temperatureNiobium-titanium, about 4 K | Why it has to be superconductingA stable, powerful field no normal magnet can hold |
| WhereParticle accelerators | Material and temperatureNiobium-titanium, about 2 K | Why it has to be superconductingBending beams at energies resistive magnets cannot reach |
| WhereFusion magnets | Material and temperatureREBCO tape, about 20 K | Why it has to be superconductingStronger fields mean a smaller, cheaper reactor |
| WhereMaglev transport | Material and temperatureVaries by system | Why it has to be superconductingLift and guidance with no contact and no friction |
The industry already runs on cold
Room temperature would make superconductors ubiquitous rather than possible. These applications justify the cryogenics and have done for forty years.
The fusion case is the clearest recent example. In September 2021, Commonwealth Fusion Systems and MIT's Plasma Science and Fusion Center ramped a rare-earth barium copper oxide (REBCO) magnet to a sustained field of over 20 tesla, using 267 kilometres of superconducting tape. Stronger magnets mean a smaller machine for the same plasma performance, which is what makes privately funded reactors conceivable at all — the point our guide to nuclear fusion describes as the technical driver behind the sector's funding boom.
The same logic runs through the Large Hadron Collider, whose beam-bending magnets operate colder than deep space. And it is why quantum computing is tangled up with this subject at all: the most industrially mature qubit is a superconducting circuit, which is exactly why it has to live at 10–20 millikelvin, as set out in our comparison of qubit types.
What Room Temperature Would Actually Change
Assume somebody succeeds. What follows is not "better gadgets."
The grid stops leaking. Transmission losses of several per cent of all generated electricity disappear, which is equivalent to building substantial generation capacity without burning anything.
Magnets get cheap. MRI without a liquid-helium supply chain changes what a hospital in a low-income country can own. Fusion magnets, already the enabling technology, get radically simpler.
New things become possible. Lossless energy storage in circulating currents, frictionless transport, and magnetic fields strong enough for applications nobody currently designs for because the cooling makes them absurd.
The honest caveat is that a room-temperature superconductor would also need to be manufacturable, mechanically robust, and able to carry high current in a strong magnetic field before any of that followed. A material that superconducts at 293 K but fails above a trivial current, or can only be made as a microscopic flake, would be a Nobel Prize and not a power line. Critical temperature is the headline, but critical current and critical field decide what gets built.
The Bottom Line
We do not have room-temperature superconductors because the critical temperature is set by a tug of war between electron pairing and thermal energy, and nobody yet knows how to design a material that wins it at 293 K. That is a genuine open problem in physics, not a funding gap or a conspiracy.
What the last few years actually demonstrated is more encouraging than the headlines suggest. LK-99 was a misread measurement, corrected in public in six weeks by labs on four continents — self-correction working at speed. The Rochester retractions were a real failure, and the people who forced the correction were the co-authors and graduate students closest to the work. And in 2026, a 33-year-old record moved, using a technique that might apply to materials we already have.
The practical advice is to read any future announcement for three things: whether the sample was characterised well enough to rule out impurities, whether it works at ambient pressure, and whether the state persists without special handling. LK-99 failed the first, hydrides fail the second, and the 2026 record currently fails the third. More context on the underlying science at our physics hub.
Frequently Asked Questions
What is a room-temperature superconductor?
A material with exactly zero electrical resistance at roughly 293 K — ordinary indoor temperature — and at normal atmospheric pressure. Both conditions matter. Superconductors that work near room temperature already exist under extreme pressure, and superconductors that work at ambient pressure already exist at low temperature. No material has yet combined both, which is the precise reason the problem is still open.
Was LK-99 a hoax?
No, and that distinction is worth preserving. The Korean team made real measurements and interpreted them incorrectly. Their samples contained copper sulfide, which changes structure near 385 K and drops in resistivity by three to four orders of magnitude at that point — a transition that looks superconducting but is not. When the Max Planck Institute grew pure single crystals, the material turned out to be an insulator. That is an error, not fraud.
Why do superconductors need to be so cold?
Because superconductivity depends on electrons binding into pairs that move through a material without scattering, and heat is random motion that breaks those pairs. The critical temperature is simply the point where thermal energy overwhelms the pairing. It is not an engineering limitation that better equipment could remove — it is the mechanism itself, which is why raising it requires a different material rather than a better fridge.
Do we already use superconductors for anything?
Extensively. Every MRI scanner uses superconducting magnets cooled to around 4 K. Particle accelerators including the Large Hadron Collider use them to bend beams. Fusion companies use high-temperature superconducting tape to build magnets above 20 tesla, which is what makes compact reactor designs possible. These applications have justified the cost of cryogenic cooling for decades.
What happened with the 2026 record?
In March 2026, researchers at the University of Houston raised the ambient-pressure record from 133 K to 151 K, published in PNAS. They used pressure quenching — compressing the material, then releasing the pressure rapidly at low temperature to lock in a higher-Tc arrangement. The state is metastable: it survived at least three days in liquid nitrogen but degraded at warmer temperatures. It is a significant result and still about 142 degrees short of room temperature.
How close are we to a room-temperature superconductor?
Nobody can give a credible timeline, and anyone who does is guessing. The most honest summary is that there is no theoretical barrier known to forbid one, no theory capable of predicting where to find one, and no current candidate that works at ambient pressure without special handling. Progress has historically come in sudden jumps after long plateaus, which makes the field genuinely unpredictable in both directions.
Sources
- University of Houston Physicists Break Superconductivity Temperature Record — University of Houston
- Room-Pressure Superconductor Breaks Temperature Record — American Physical Society, Physics
- 'Room-temperature superconductor' LK-99 fails replication tests — Physics World, IOP Publishing
- A controversial room-temperature superconductor result has been retracted — Science News
- Superconductivity at 250 K in lanthanum hydride under high pressures — Drozdov et al., Nature 569 (2019)
- World's strongest HTS magnet reaches 20 tesla — Commonwealth Fusion Systems
