| Apr 30, 2026 |
A research team has directly observed the Meissner effect in two-dimensional superconductors using a new high-sensitivity magnetometry method.
(Nanowerk News) A research team has directly observed the Meissner effect in two-dimensional superconductors, capturing magnetic signatures that had remained inaccessible to standard instruments. The work, carried out at the High Magnetic Field Laboratory of the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, with collaborators at Nanjing University and Yanshan University, appears in Advanced Materials (“Probing the Meissner Effect in Microscale Two‐Dimensional van der Waals Superconductors”).
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The Meissner effect is the way a superconductor expels magnetic fields from its interior when it cools below its critical temperature, so that a magnet placed nearby is pushed away rather than penetrating the material.
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Key Findings
- The team directly observed the Meissner effect in two-dimensional superconductors using a high-sensitivity magnetometry technique that surpasses the limits of established tools.
- Working with 2M-WS2, a structural phase of layered tungsten disulfide, the researchers obtained magnetic measurements from samples as thin as 4 nanometers.
- The method captured clear magnetic hysteresis loops in microscale samples, exposing type-II superconducting behavior that had previously been inferred only from electrical transport.
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Two-dimensional van der Waals superconductors have drawn intense attention in condensed matter physics for the unusual quantum behavior they exhibit at low dimensions. Their very small volume, however, produces magnetic signals so weak they fall below the resolution of conventional instruments.
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As a result, superconductivity in these systems has been inferred mainly from zero-resistance transport measurements, leaving the Meissner effect, one of the two defining hallmarks of superconductivity, beyond direct experimental reach and limiting access to the materials’ intrinsic properties.
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| Ultrasensitive detection of the Meissner effect in two-dimensional superconductors. (Image: WANG Kang) (click on image to enlarge)
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The team built a high-sensitivity magnetic measurement method paired with a theoretical framework designed for anisotropic superconducting systems. The approach extends a compact dynamic cantilever magnetometry technique the same group developed earlier. It allows researchers to quantitatively extract magnetization, magnetic susceptibility, and diamagnetic screening efficiency from samples that produce only minute magnetic responses.
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The method reaches a magnetic moment sensitivity of about 1.1×10⁻¹⁷ A·m² at 1 tesla and an AC susceptibility sensitivity of 9.4×10⁻¹⁷ A·m²/T at the same field. Both figures exceed the detection limits of existing techniques and brought samples that were previously too small or too thin to characterize magnetically within range of measurement.
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Using 2M-WS2, a specific structural phase of layered tungsten disulfide, the researchers recorded clear magnetic hysteresis loops in microscale samples around one hundred nanometers thick. The loops are the characteristic response of a type-II superconductor and had not previously been resolved in two-dimensional superconducting samples at that scale.
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In samples thinned to 4 nanometers, the team obtained quantitative readings of magnetic susceptibility and diamagnetic screening efficiency, providing direct experimental evidence of the Meissner effect in two-dimensional superconductors.
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According to the researchers, the work resolves a standing difficulty in detecting magnetic signatures of superconductivity in low-dimensional systems and offers a broadly applicable approach for measuring weak magnetic responses in similar materials.
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