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    How superconductivity works

    A superconductor carries direct current with no energy loss and expels magnetic fields once it is cooled below a critical temperature.[1] As of October 2026 the best material that works at normal pressure superconducts at 151 K (about -122 °C), still roughly 140 °C short of room temperature.[2][3]

    Editor reviewedUpdated Materials sciencePhysicsScience

    What a superconductor does

    A superconductor is a material that, below a certain “critical temperature”, it carries direct current with no energy loss at all, and it pushes magnetic fields out of itself.[1]

    The effect was first seen in 1911 by Heike Kamerlingh Onnes.[4] Today superconducting magnets sit inside MRI scanners and steer particle beams in accelerators.[5]

    The two defining signatures are zero DC resistance below the critical temperature (Tc) and expulsion of magnetic flux (the Meissner effect).[1] Both matter for evidence: a resistance drop alone can come from other effects, which is one reason claims of new superconductors are checked against magnetisation as well as transport data.[6] The main established applications use superconducting magnets, in MRI and in accelerator beam lines.[5]

    Why electrons pair up

    In 1957 three physicists explained how it works in ordinary superconductors. Electrons, which normally repel each other, form pairs held together by tiny vibrations of the atoms around them. The pairs move together through the material without bumping into anything.[7]

    BCS theory (1957) describes conventional superconductivity as phonon-mediated electron pairing: Cooper pairs condense into a coherent state that carries current without dissipation.[7] Twisted bilayer graphene, the first purely carbon-based 2D superconductor, has a phase diagram with superconducting domes similar to that of the cuprates found in 1986, which makes it a tunable test bed for high-temperature superconductivity.[8][9]

    The race for higher temperatures

    Cooling is the catch. In 1986 scientists found copper-oxide ceramics (“cuprates”), some of which work above the temperature of liquid nitrogen (-196 °C).[8] Hydrogen-rich compounds can superconduct at about 250 K (-23 °C), but only when squeezed to roughly 1.7 million times atmospheric pressure.[10]

    In March 2026 a University of Houston team reported 151 K at normal pressure in a mercury cuprate called Hg-1223. They squeezed the material, cooled it and then released the pressure, and the improved state stayed.[2][11]

    Three families define the Tc landscape. Cuprates hold the ambient-pressure record: Hg-1223’s 133 K stood from 1993 until a March 2026 PNAS paper reported 151 K after “pressure quenching”, retaining a pressure-enhanced state after decompression.[2][11] Superhydrides reach higher Tc, about 250 K in LaH10, but at around 170 GPa, after H3S reached 203 K.[10] Bilayer nickelates are the newest family. La3Ni2O7 reached about 80 K under pressure in 2023, and strained thin films have shown ambient-pressure onsets of up to 63 K by 2026.[12][13] See nickelate-superconductors.

    Why room temperature is the prize

    A superconductor that worked at room temperature would remove expensive cooling and could change power grids and medical imaging.[14] The best normal-pressure materials are still about 140 °C too cold.[3] That gap is why claims like lk-99 in 2023 caused so much excitement, and why they get checked so hard.[15][16]

    The open questions are whether any mechanism allows ambient-pressure Tc near 300 K, and whether metastable phases such as pressure-quenched cuprates can be stabilised in useful forms.[3][11] The field’s recent history includes a viral false positive, LK-99, and a retracted Nature paper on lutetium hydride. In both cases independent groups could not reproduce the claimed superconductivity.[6][17] The room-temperature superconductivity debate covers this in detail.

    Questions readers ask

    What makes a superconductor different from a good conductor like copper?

    A superconductor below its critical temperature carries direct current with no energy loss at all, and it expels magnetic fields.[1]

    What is the highest temperature at which a superconductor works?

    Lanthanum hydride superconducts at about 250 K, but only at around 170 GPa of pressure. At ordinary pressure the record is 151 K, reported in March 2026 for a mercury cuprate.[10][2]

    Where are superconductors used today?

    Superconducting magnets are used in MRI scanners and to steer beams in particle accelerators and synchrotrons.[5]

    Why do electrons flow without resistance?

    In conventional superconductors, electrons form pairs bound by lattice vibrations, and those pairs move through the material without resistance.[7]

    Sources

    Each numbered claim is a statement we checked against the sources listed with it. Status shows how well established it is.

    1. [1]

      Superconductivity is the property of certain materials to carry direct current with no energy loss when cooled below a critical temperature; superconductors also expel magnetic fields as they enter the superconducting state. confirmedas of 2026-10-10

    2. [2]

      In March 2026 a University of Houston team reported a superconducting transition temperature of 151 K at ambient pressure in the mercury cuprate Hg-1223, beating the 133 K ambient-pressure record that had stood since 1993. reportedas of 2026-10-10

    3. [3]

      Even after the 151 K record, roughly 140 degrees Celsius still separate the best ambient-pressure superconductors from room temperature (about 300 K). confirmedas of 2026-10-10

    4. [4]

      Superconductivity was first observed in 1911 by Heike Kamerlingh Onnes, who received the 1913 Nobel Prize in Physics. confirmedas of 2026-10-10

    5. [5]

      Superconducting magnets are used in MRI machines and to guide particle beams in synchrotrons and accelerators. confirmedas of 2026-10-10

    6. [6]

      An August 2023 study attributed LK-99's sudden resistivity drop to a structural phase transition of a copper sulfide (Cu2S) impurity near 385 K, and observed no zero resistance. confirmedas of 2026-10-10

    7. [7]

      In 1957 BCS theory explained conventional superconductivity as electrons forming pairs held together by lattice vibrations (phonons), which move through the material without resistance. confirmedas of 2026-10-10

    8. [8]

      In 1986 scientists discovered copper-oxide (cuprate) superconductors, some of which work above the temperature of liquid nitrogen. confirmedas of 2026-10-10

    9. [9]

      The phase diagram of magic-angle graphene shows similarities to that of the cuprate high-temperature superconductors, including superconducting domes, making it the first purely carbon-based 2D superconductor. confirmedas of 2026-10-10

    10. [10]

      Lanthanum hydride (LaH10) was reported in 2018-2019 to superconduct at about 250 K, but only under about 170 GPa of pressure, beating the earlier 203 K record set by H3S. confirmedas of 2026-10-10

    11. [11]

      The 151 K result used "pressure quenching", in which the material is squeezed to enhance superconductivity, cooled, and then released so the enhanced state is retained at ambient pressure; it was published in PNAS on 9 March 2026. reportedas of 2026-10-10

    12. [12]

      The bilayer nickelate La3Ni2O7 was discovered in 2023 to superconduct near 80 K, but only under high pressure. confirmedas of 2026-10-10

    13. [13]

      In April 2026 a SUSTech-led team reported (La,Pr)3Ni2O7 films with a superconducting onset of 63 K and zero resistance at 37 K at ambient pressure, published in National Science Review. reportedas of 2026-10-10

    14. [14]

      Most superconductors must be cooled to extremely low temperatures, which makes them expensive and difficult to use; the University of Houston team says room-temperature superconductivity could dramatically improve power grids, medical technologies and energy systems. confirmedas of 2026-10-10

    15. [15]

      On 22 July 2023 a preprint claimed that LK-99, a copper-doped lead apatite, was a superconductor at 400 K (127 °C) or above at ambient pressure, attributing this to a slight structural distortion from copper substituting for lead. confirmedas of 2026-10-10

    16. [16]

      In August 2023 researchers who grew phase-pure single crystals of the LK-99 compound found them highly insulating and transparent and ruled out superconductivity. confirmedas of 2026-10-10

    17. [17]

      On 7 November 2023 Nature retracted a March 2023 paper claiming room-temperature superconductivity in a nitrogen-doped lutetium hydride, after eight of its 11 authors requested retraction; most other groups had failed to reproduce the result. confirmedas of 2026-10-10

    Revision history (1)
    1. Page created.

    Created Oct 10, 2026. Last reviewed by an editor on Oct 10, 2026. Next scheduled review: Jan 10, 2027.

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    "How superconductivity works." ContentLora, updated Oct 10, 2026. https://contentlora.com/explain/how-superconductivity-works

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