Reference
Materials, evidence, and the limits.
A useful material has to satisfy more than a transition temperature. Here is the published record, how we assess our models, and what superconducting devices require in practice.
The record
The temperature record
The major ambient-pressure milestones since 1911. Temperature is one measure of progress; stability and a workable manufacturing process determine what an engineer can use.
Liquid nitrogen77 K
A warm room293 K
158 K
to room temperature
Hg
1911 · 4.2 K
Hg-1223
1993 · 135 K
Hg-1223, pressure-quenched
2026 · 151 K
about three days at 77 K
1911
1950
2026
Highest measured transition temperature at ambient pressure, by year of first report. Linear scale, zero at the foot. The dashed point is drawn hollow because it is a metastable phase.
How the record was built
Progress has been uneven. Conventional superconductors raised the record gradually; the cuprates transformed it in a few years. The durable ambient-pressure record then remained unchanged for decades, even as conductor manufacturing and device engineering continued to advance.
| Year | Material | Tc |
|---|---|---|
| 1911 | Hg | 4.2 K |
| 1941 | NbN | 16 K |
| 1954 | Nb₃Sn | 18.3 K |
| 1973 | Nb₃Ge | 23.2 K |
| 1986 | La-Ba-Cu-O | 35 K |
| 1987 | YBCO | 92 K |
| 1988 | Tl-2223 | 122 K |
| 1993 | Hg-1223 | 135 K |
Download the temperature record (CSV)Published measurements, including the separately qualified pressure-quenched result.
The chain above, written out material by material: The ambient-pressure superconductor record, 1911 to 2026.
A pressure-prepared phase at ambient pressure
In 2026, a group in Houston reported 151 K in Hg-1223 at ambient pressure. The material was first compressed in a diamond anvil cell, then decompressed at low temperature to retain the pressure-prepared phase. This pressure-quenching process is central to interpreting the result.
The phase survives about three days at 77 K and is lost above 200 K; the reported samples are flakes tens of microns across. The result extends the measured record, but does not establish a durable, manufacturable conductor. It also illustrates why processing belongs alongside composition in a materials search.
The empty band
The durable record of 135 K, set in 1993, held for 33 years. A warm room is still 158 kelvin above it. Our internal discovery program searches for new materials in this gap. Customer programs also address an immediate problem: making known superconductors meet demanding device and manufacturing requirements.
The proof
How a prediction is checked
The platform ranks materials and processes against engineering requirements. Our discovery research draws on the MEL framework to search for new materials; it is a distinct part of our work. Evaluate a prediction against published measurements, test it in a new experiment, and examine the independent evidence for its physical basis. Each answers a different question.
27 cited publications · 7 independent evidence groups · Sources and limits below
Forward, committed before the instrument runs
Backward, the record goes in with part of it withheld, and comes back
A century of experimental evidence
Published measurements provide the baseline for evaluating a model. NIMS SuperCon catalogs around thirty thousand records; the original papers supply the conditions and measurement criteria needed to interpret them. The size of that public corpus is not a statement about our training set.
- SuperCon, the reference databaseRoughly thirty thousand records of measured superconductors, curated at Japan’s National Institute for Materials Science.
- arXiv · cond-mat.supr-conThe live preprint stream where the field publishes first. New measurements arrive here daily.
- Physical Review LettersOne of the journals of record, and where the independent measurement cited below was published.
Four checks you can run from your desk
Before any closed test, the framework has to agree with what is already measured. Below are four places where the framework says something the literature can answer, with the paper that answers it. Bi-2212 comes first because it is the material on our instruments; the last row is a nickelate, not a copper oxide. Every row is a link, and nothing here is the output of a run.
| Material | The framework says | The record says | Source |
|---|---|---|---|
| Bi-2212 | The framework saysThe charge pattern moves with doping, 0.30 down to 0.25 r.l.u. | The record saysIt does | Phys. Rev. B, 2022 ↗ |
| YBCO | The framework saysThe pattern is bond-centered, d-form | The record saysMeasured d-form | Nature Materials, 2015 ↗ |
| LBCO at one-eighth | The framework saysThree orders fight here, and pairing loses | The record saysThe transition collapses | Nature, 1995 ↗ |
| La₃Ni₂O₇ | The framework saysNot a copper oxide, and the same machinery applies | The record saysSuperconducts near 80 K, under pressure | Nature, 2023 ↗ |
The literature we build on
Every brief the platform takes lands in a field somebody has already measured: decades of published work on films, interfaces, junctions and wires. These are the papers we check ourselves against, grouped by problem class, and every link was opened and verified before it shipped. Reading them is the fastest way to see the standard our answers have to meet.
Nitride films
Superconducting nitride films, NbN and NbTiN, are the working layer of single-photon detectors and some superconducting electronics, and film quality decides everything downstream.
- Picosecond superconducting single-photon optical detectorGol’tsman, G. N. et al. · Appl. Phys. Lett. 79, 705 (2001)
- Superconducting nanowire single-photon detectors: physics and applicationsNatarajan, C. M., Tanner, M. G. & Hadfield, R. H. · Supercond. Sci. Technol. 25, 063001 (2012)
- Superconducting properties and chemical composition of NbTiN thin films with different thicknessZhang, L., Peng, W., You, L. X. & Wang, Z. · Appl. Phys. Lett. 107, 122603 (2015)
Superconductor on semiconductor
Growing a superconductor against a semiconductor without ruining either is its own field, and the cleanest results are epitaxial.
- Epitaxy of semiconductor–superconductor nanowiresKrogstrup, P. et al. · Nat. Mater. 14, 400 (2015)
- Hard gap in epitaxial semiconductor–superconductor nanowiresChang, W. et al. · Nat. Nanotechnol. 10, 232 (2015)
- Two-dimensional epitaxial superconductor-semiconductor heterostructures: a platform for topological superconducting networksShabani, J. et al. · Phys. Rev. B 93, 155402 (2016)
Junctions
Two superconductors and the barrier between them: the working element of qubits and SQUIDs, and the place devices fail.
- Possible new effects in superconductive tunnellingJosephson, B. D. · Phys. Lett. 1, 251 (1962)
- Grain boundaries in high-Tc superconductorsHilgenkamp, H. & Mannhart, J. · Rev. Mod. Phys. 74, 485 (2002)
- Superconducting quantum bitsClarke, J. & Wilhelm, F. K. · Nature 453, 1031 (2008)
- Materials in superconducting quantum bitsOliver, W. D. & Welander, P. B. · MRS Bull. 38, 816 (2013)
Making known materials usable
The gap between a superconductor and a conductor anybody can wind is decades of applied work on wires, tapes and strain.
- High-Tc superconducting materials for electric power applicationsLarbalestier, D., Gurevich, A., Feldmann, D. M. & Polyanskii, A. · Nature 414, 368 (2001)
- A review of the properties of Nb₃Sn and their variation with A15 composition, morphology and strain stateGodeke, A. · Supercond. Sci. Technol. 19, R68 (2006)
- Materials science challenges for high-temperature superconducting wireFoltyn, S. R. et al. · Nat. Mater. 6, 631 (2007)
- Isotropic round-wire multifilament cuprate superconductor for generation of magnetic fields above 30 TLarbalestier, D. C. et al. · Nat. Mater. 13, 375 (2014)
Machine learning before us
Transition temperatures have been predicted from the SuperCon database before, and the large structure-discovery models are real. We cite the efforts this platform is most often compared to; the FAQ says where ours differs.
- Machine learning modeling of superconducting critical temperatureStanev, V. et al. · npj Comput. Mater. 4, 29 (2018)
- A data-driven statistical model for predicting the critical temperature of a superconductorHamidieh, K. · Comput. Mater. Sci. 154, 346 (2018)
- Scaling deep learning for materials discoveryMerchant, A. et al. · Nature 624, 80 (2023)
Where the training data comes from
Our models draw on published measurements, partner experiments, and our own computational campaigns. Results are useful only with their conditions and provenance attached. Customer data and rights to program results are governed by the agreement; our internal discovery work creates a separate body of evidence.
Three things we hold to
Physics constrains the search
Learned models help rank a large space of possibilities. Physical constraints narrow what deserves an experiment. Neither a high ranking nor a plausible mechanism establishes that a material will work.
Prediction has to precede measurement
Agreement with known materials is a necessary check. A prospective test asks a harder question: does a prediction, recorded with its uncertainty before the experiment, survive a new measurement?
Unsuccessful experiments are evidence
A route that fails to form the intended phase still constrains the next search. We retain experimental conditions and outcomes so the model can learn from the full program, rather than only its best result.
From research to intellectual property
Our internal search develops materials and processes that can become owned intellectual property. Experimental evidence and patent protection serve different purposes; neither substitutes for the other. The underlying framework is licensed exclusively from Hyunsung TNC, where development began in 2006. Unpublished filing details remain confidential.
The closed test
We use retrospective and prospective tests. In the retrospective direction, established superconductors are evaluated with part of the record withheld; the platform returns its result in minutes for comparison with published measurements. In the prospective direction, a prediction and its uncertainty are recorded before the instrument runs. Comparisons must account for what was measured: onset, midpoint, zero resistance, and the Meissner response are different criteria. We do not publish a precision figure that collapses those distinctions.
The scientific basis for MEL
The studies below examine how charge order, lattice motion, and superconductivity interact. Their relevance to MEL differs: one reports an effect consistent with a central prediction; others provide related experimental observations, theoretical context, or computational precedents. Each group states what its evidence supports. None is an independent test of the full SuperMatics platform.
Independent experimental result consistent with a central MEL prediction
Superconductivity is measured raising the phase coherence of the charge order while lowering its amplitude. MEL holds those two apart and predicts that exact split, which is what makes this the closest outside result to the framework. The group at Stanford and SLAC did not set out to test MEL, and we had no part in the work.
Charge and lattice, watched moving together in two copper oxides
In YBCO the lattice’s slow fluctuations change as the material crosses into superconductivity, and change again where the charge order sits. In LSCO the tilt of the CuO₆ octahedra tracks both the electron-phonon coupling and the charge correlations under it. MEL is a claim about an electron lattice; this is the lattice half of it.
- Understanding the superconductivity and charge density wave interaction through quasi-static lattice fluctuationsPorter, Z. et al. · Proc. Natl. Acad. Sci. 121, e2412182121 (2024)
- Enhanced electron–phonon coupling due to layered-perovskites octahedral tilting in hole doped cuprate superconductorIsha et al. · J. Phys.: Condens. Matter 38, 145402 (2026)
The same intertwined state, in a kagome metal
Short-range charge correlations survive across the second superconducting dome after the long-range order is gone. Short-range and surviving is the state MEL is built on, and here it is in a kagome metal rather than a copper oxide.
The amplification derived independently, from another starting point
Electronic density fluctuations are shown to enhance the electron-phonon coupling and the pairing interaction that comes out of it. The amplification MEL leans on is derived here from a different starting point.
A finite-q lattice instability, measured directly
A softened finite-momentum phonon is identified as the microscopic origin of charge order in CsV₃Sb₅. Finite momentum is where MEL says the physics happens, and this is a direct measurement of it.
Modulated pairing from a neighboring theory
Kagome sublattice structure is shown to generate a modulation of superconducting pairing inside the unit cell. A different lattice, a different method, and a modulated pairing state falls out of it.
Foundational review
The review that settled why charge, spin, nematic and pair-density-wave orders in these materials are better read as intertwined with superconductivity than as competing with it. MEL is a quantitative framework built on that reading.
Computational precedents, not evidence for MEL
Prediction to synthesis has been done before, and at scale: a kagome superconductor predicted and then made, and a screening workflow built on learned Eliashberg spectral functions with stability calculations and experimental follow-up behind it. This is the standard our own workflow has to beat. Neither paper is ours, and neither is evidence for the physics.
These papers are independent work, not SuperMatics results. A measurement consistent with a central MEL prediction does not validate the entire framework or establish one of our proposed materials as superconducting. Our own write-ups are being revised. The final two papers illustrate computational workflows; they are not evidence for MEL.
The short version of all of this is in the FAQ
Applications
Where superconductors become devices
Explore where superconductors are already used, what has been demonstrated, and what still depends on a material we do not yet have. Select a status or open an application to see the engineering question behind it.
Some of these applications are commercial products; others are demonstrations or depend on materials that do not yet exist. Their constraints include temperature, magnetic field, current, cost, and manufacturability. Defining those requirements is the starting point for a platform search.
Each of these has its own page now: what a superconductor buys there, what it is wound from, and what is still stopping it. Read the fields one at a time, or take the map below.
Medicine
- In service today
MRI
Most scanners are superconducting magnets. More than 30,000 are installed.
Niobium-titanium and affordable MRI · Physics in Perspective ↗The engineering question
Where the platform comes in
Deployed at scale, and capped by cost and cold. Written down as a number, that cap is a brief.
See how a brief runs - In service today
Particle therapy
A superconducting gantry brought a heavy-ion treatment room from 600 tonnes down to about 300.
A compact superconducting rotating gantry · NIRS ↗The engineering question
Where the platform comes in
Deployed at scale, and capped by cost and cold. Written down as a number, that cap is a brief.
See how a brief runs - In service today
NMR spectrometers
The magnet that resolves a protein structure runs at a few kelvin.
The first 1.2 GHz protein NMR data · Bruker ↗The engineering question
Where the platform comes in
Deployed at scale, and capped by cost and cold. Written down as a number, that cap is a brief.
See how a brief runs - In service today
Biomagnetic sensing
SQUIDs read the magnetic field of brain activity through the skull.
Superconducting magnetometers for brain investigations · PMC ↗The engineering question
Where the platform comes in
Deployed at scale, and capped by cost and cold. Written down as a number, that cap is a brief.
See how a brief runs
Energy and the grid
- In service today
Transmission cable
In the ground under Shanghai, Essen and Long Island. Rare because of the cold.
A kilometer of superconducting cable under Essen · KIT ↗The engineering question
Where the platform comes in
Deployed at scale, and capped by cost and cold. Written down as a number, that cap is a brief.
See how a brief runs - In service today
Fault-current limiters
Goes normal in a millisecond and swallows a short circuit.
Fault-current limiters against a real short circuit · Energies ↗The engineering question
Where the platform comes in
Deployed at scale, and capped by cost and cold. Written down as a number, that cap is a brief.
See how a brief runs - Built and demonstrated
Wind generators
A 3.6 MW superconducting rotor ran on a Danish turbine for 650 hours.
A superconducting rotor on a 3.6 MW turbine · EcoSwing ↗The engineering question
Where the platform comes in
The engineering is done and the economics are not. What separates a demonstration from a product is a better conductor, and a better conductor is a search we can run.
See how a brief runs - Built and demonstrated
Magnetic energy storage
Current parked in a loop and handed back in milliseconds, for power quality.
The engineering question
Where the platform comes in
The engineering is done and the economics are not. What separates a demonstration from a product is a better conductor, and a better conductor is a search we can run.
See how a brief runs
Compute and sensing
- Built and demonstrated
Quantum computers
Most of the largest processors are superconducting circuits, held near absolute zero.
Who is leading superconducting quantum computing · EPJ Quantum Technology ↗The engineering question
Where the platform comes in
The engineering is done and the economics are not. What separates a demonstration from a product is a better conductor, and a better conductor is a search we can run.
See how a brief runs - In service today
Photon counting
Superconducting nanowires count single photons for quantum links and lidar.
Nanowire detectors at 98 percent efficiency · NIST ↗The engineering question
Where the platform comes in
Deployed at scale, and capped by cost and cold. Written down as a number, that cap is a brief.
See how a brief runs - Waiting on a material
Superconducting logic
Switching at a fraction of the energy of silicon. Demonstrated for decades, never volume-made.
Superconducting logic and what it costs to switch · PMC ↗The engineering question
Where the platform comes in
The machine is designed and the material is missing. Here the brief is not a cost target, it is the conductor itself.
See how a brief runs - In service today
Telescope detectors
Sensors that measure one photon by the heat it leaves behind.
The SPT-3G focal plane, 16,000 detectors · arXiv ↗The engineering question
Where the platform comes in
Deployed at scale, and capped by cost and cold. Written down as a number, that cap is a brief.
See how a brief runs
Transport
- Built and demonstrated
Maglev
Japan’s superconducting maglev reached 603 km/h on a test track.
The superconducting maglev · JR Central ↗The engineering question
Where the platform comes in
The engineering is done and the economics are not. What separates a demonstration from a product is a better conductor, and a better conductor is a search we can run.
See how a brief runs - Waiting on a material
Electric aircraft
A megawatt motor light enough to fly needs a cryostat that survives a wing.
The high-efficiency megawatt motor · NASA ↗The engineering question
Where the platform comes in
The machine is designed and the material is missing. Here the brief is not a cost target, it is the conductor itself.
See how a brief runs - Built and demonstrated
Ship propulsion
A 36.5 MW superconducting motor was built and tested for naval use.
A 36.5 MW propulsion motor at full power · AMSC ↗The engineering question
Where the platform comes in
The engineering is done and the economics are not. What separates a demonstration from a product is a better conductor, and a better conductor is a search we can run.
See how a brief runs
Science and heavy industry
- In service today
Particle accelerators
1,232 superconducting dipoles bend the beam around 27 km at CERN.
The LHC’s superconducting dipoles · CERN ↗The engineering question
Where the platform comes in
Deployed at scale, and capped by cost and cold. Written down as a number, that cap is a brief.
See how a brief runs - Built and demonstrated
Fusion magnets
Twenty tesla, and the reason a compact tokamak is credible at all.
A 20 tesla magnet for a compact tokamak · MIT ↗The engineering question
Where the platform comes in
The engineering is done and the economics are not. What separates a demonstration from a product is a better conductor, and a better conductor is a search we can run.
See how a brief runs - In service today
Magnetic separation
High-gradient magnets pull iron out of clay at industrial rates.
Superconducting separation of kaolin · Clay Minerals ↗The engineering question
Where the platform comes in
Deployed at scale, and capped by cost and cold. Written down as a number, that cap is a brief.
See how a brief runs - In service today
Induction heating
Heats a metal billet far more efficiently than a copper coil.
Induction heaters with high-Tc magnets · SN Applied Sciences ↗The engineering question
Where the platform comes in
Deployed at scale, and capped by cost and cold. Written down as a number, that cap is a brief.
See how a brief runs
What we do with a brief is on the platform page