Thinner Means Stronger: How Ultrathin Films Beat Magnetic Fields ⚡ экспресс
In the layered superconductor PdTe2, quantum confinement in thin films changes the electrons' g-factor, making the Pauli limit field dependent on thickness. Measurements at 20 mK showed that as the thickness decreased from 50 to 19 nm, the upper critical field increased more than 10-fold. Modeling revealed the influence of both orbital and spin (Zeeman) mechanisms of superconductivity breakdown, with the spin role proving key. This points to the possibility of discovering exotic superconducting states where field enhancement is linked to non-trivial pairing symmetry.
Superconductors are materials that transmit current without loss. In the 1950s, John Bardeen and his colleagues explained that electrons in them pair up, like dance partners. However, Wolfgang Pauli showed that a strong enough magnetic field, like a whirlwind, would tear the pair apart — this is the Pauli limit. But in layered PdTe₂, it's different. When rolled into a film just 19 nanometers thick, the electron pairs find themselves in a cramped room: there's no room to move, the bond strengthens, and you need a hurricane to pull them apart. In the experiment, such a film withstood a field 10 times stronger than a thicker one.
This discovery draws a thread from nanometer-thin films to galactic beacons, touching on the laws of the Standard Model and the concept of entropy in quantum systems.
🎯 A 19-nm-thick PdTe₂ film is five times thinner than the shell of the flu virus. Individual layers of this material can be peeled off with adhesive tape, paving the way for flexible superconducting electronics.