Article
Is there a room-temperature superconductor?
There is no established room-temperature superconductor operating at ambient pressure. The credible results discussed here remain either cryogenic or dependent on extreme pressure; the most prominent room-temperature claims were retracted or failed independent testing. [1][3][4][5][6][7][8]
- Published
- Reading time
- 5 min
- Cited
- 10 sources
The answer needs both temperature and pressure
A room-temperature superconductor would retain superconductivity under ordinary thermal conditions. For most proposed cables and magnets, it would also need to work at ambient pressure. Those are separate requirements. A high transition temperature measured while a tiny sample is compressed between diamond anvils does not establish a conductor that can be wound and operated outside the apparatus. Equally, an ambient-pressure measurement on a cold sample does not mean the sample is at ambient temperature. Omitting either axis turns a specific laboratory result into a different and much broader claim. [1][3][4]
The evidence needs to identify superconductivity, not merely a change in resistance or an unusual response to a magnet. The strongest reports combine electrical and magnetic measurements, examine how the transition responds to magnetic field, and state sample preparation and measurement conditions. A resistance drop need not reach zero, while ordinary magnetism can also make a fragment move near a magnet. The hydride papers, the retraction notices, and the LK-99 replication studies show why corroborating measurements and reproducibility are necessary before a headline becomes an established result. [3][4][5][6][7][8]
Cuprates remain the ambient-pressure benchmark
The mercury-based cuprate Hg-1223 supplied the long-standing ambient-pressure reference. Schilling and colleagues reported in Nature a maximum transition near 133 kelvin in 1993, supported by resistivity and magnetic susceptibility. That was far below everyday temperature despite being high relative to earlier superconductors. The result belongs to the layered copper-oxide family, not to a material that could simply be drawn into ordinary metal wire. The historical record and the development of practical cuprate conductors are related subjects, but improvements in conductor processing do not necessarily raise the highest measured transition temperature. [2][9]
The University of Houston pressure-quench paper published in PNAS in 2026 reports an ambient-pressure resistive onset up to 151 kelvin in Hg-1223. High pressure was used during treatment and then released while the sample was cold. The retained state is metastable and has limited thermal and temporal stability. Its headline onset should not be substituted for a zero-resistance temperature or an independently measured bulk magnetic transition at that same temperature. This is a reported advance in a known cuprate under specified conditions, not room-temperature superconductivity and not a demonstrated manufacturing route for wire. [1]
Hydrides reach higher temperatures under pressure
Sulfur hydride made a major contribution to the high-pressure record. In 2015, Drozdov and colleagues reported in Nature a superconducting transition of 203 kelvin, with that magnetic onset measured at 155 GPa. They observed zero resistance, magnetic-field suppression of the transition, and an isotope shift consistent with an electron-phonon mechanism. The paper argued that the high-temperature phase was likely H3S, formed from the starting hydrogen sulfide under pressure. The composition assignment and the measurement conditions belong in the description; the temperature alone does not explain what was established. [3]
In 2019, the same research group reported in Nature superconductivity around 250 kelvin in lanthanum hydride, LaH10, at about 170 GPa. Zero resistance, an isotope effect, and a lower transition under an applied magnetic field supported their interpretation. These megabar-pressure experiments show that hydrogen-rich systems can reach unusually high superconducting temperatures. They do not remove the pressure requirement or establish an ambient-pressure material. For a wire designer, a phase that exists only under extreme compression presents a different problem from selecting an available conductor, even when its laboratory transition is comparatively warm. [4]
The Dias-associated claims were retracted
The carbonaceous sulfur hydride paper associated with Ranga Dias was published in 2020 and retracted by Nature in 2022. The retraction identified an undisclosed, nonstandard background-subtraction procedure used in processing magnetic susceptibility data. The editors concluded that these issues undermined confidence in the published magnetic data as a whole. The authors disagreed with the decision. The correct summary is that the claimed result is retracted, with the stated data-processing grounds visible. Its original temperature claim should not remain in a table of established superconducting records. [5]
The nitrogen-doped lutetium hydride claim, often abbreviated LuNH, was published and retracted by Nature in 2023. Authors requesting the retraction stated that the paper did not accurately reflect material provenance, experimental measurements, and data-processing protocols. The journal also identified credible and unresolved concerns about electrical resistance data. Separately, an independent Nature study found no near-ambient superconductivity in its nitrogen-doped lutetium hydride samples under the conditions tested. These findings do not justify calling every hydride result invalid, nor should they be embellished into an unsupported allegation of fraud. They invalidate treating this particular claim as established evidence. [6][10]
LK-99 did not survive independent testing
LK-99 attracted widespread attention in 2023 as a claimed ambient-pressure, room-temperature superconductor. Subsequent work examined the composition, impurity phases, electrical behavior, and magnetic response instead of relying on videos of partial levitation. A replication study published in Superconductor Science and Technology reproduced the reported electrical and magnetic anomalies but associated them with a structural transition of copper sulfide impurities, not superconductivity. A resistance change caused by another phase is not evidence that the proposed superconducting compound has reached its transition. Identifying what is actually present in the sample is essential to interpreting the measurement. [7]
A separate study synthesized phase-pure single crystals of the copper-substituted lead phosphate and found them highly insulating, with a magnetic response characteristic of a nonmagnetic insulator plus a small ferromagnetic component. The authors ruled out superconductivity in those crystals. The studies address different parts of the original story: impurity-related transport anomalies and the properties of the intended phase. Taken together, they refute LK-99 as established evidence for ambient-pressure room-temperature superconductivity. A striking visual demonstration, a calculated electronic structure, or a suggestive resistance curve cannot replace reproducible superconducting transport and magnetic measurements. [7][8]
Why ambient pressure matters for useful wire
An engineering conductor must retain its superconducting state while it is fabricated, handled, joined, cooled, and loaded by current and magnetic field. Maintaining diamond-anvil pressures along a winding is not a demonstrated extension of the hydride experiments. Pressure used during synthesis may be manageable in principle if the useful phase survives afterward, but that survival must be measured rather than assumed. The Houston pressure-quench work explores precisely this retention problem, while explicitly reporting limits to stability. Preparation pressure, operating pressure, and storage conditions therefore need separate entries in any material assessment. [1][3][4]
Even an established ambient-pressure, room-temperature material would not automatically become useful wire. It would still need adequate current density in field, grain connectivity, mechanical tolerance, uniform conductor processing, and a credible protection strategy. Existing cuprate conductor development demonstrates the importance of those requirements without needing to predict a future discovery date. For engineers and investors, the sound approach is to keep a result's measurement conditions, evidence quality, and manufacturing status together. Temperature records are scientifically important; they are not by themselves specifications for a commercial magnet, cable, or power system. [9]
Sources
- Ambient-pressure 151-K superconductivity in HgBa2Ca2Cu3O8+δ via pressure quenchPNAS, 2026
- Superconductivity above 130 K in the Hg-Ba-Ca-Cu-O systemNature, 1993
- Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride systemNature, 2015
- Superconductivity at 250 K in lanthanum hydride under high pressuresNature, 2019
- Retraction Note: Room-temperature superconductivity in a carbonaceous sulfur hydrideNature, 2022
- Retraction Note: Evidence of near-ambient superconductivity in a N-doped lutetium hydrideNature, 2023
- Replication and study of anomalies in LK-99: the alleged ambient-pressure, room-temperature superconductorSuperconductor Science and Technology, 2024
- Single crystal synthesis, structure, and magnetism of Pb10-xCux(PO4)6OAPL Materials, 2023
- High-Tc superconducting materials for electric power applicationsNature, 2001
- Absence of near-ambient superconductivity in LuH2±xNyNature, 2023
SuperMatics: AI built for superconductors.