Thinner Means Stronger: How Ultrathin Films Beat Magnetic Fields ✛ ✎

Original: "g-Factor Enhanced Upper Critical Field in Superconducting PdTe2 due to Quantum Confinement"
arXiv:2508.07547 · 2025-08-11 · arXiv non-exclusive · independent analysis · 1 min
Scientists have found that a 19-nm-thick PdTe₂ film withstands magnetic fields 10 times stronger than a thicker sample.

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.

Similar processes occur in neutron stars — the ultra-dense remnants of dead stars. There, protons squeezed by gravity form superconducting pairs and generate colossal magnetic fields that power pulsars.

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.

\mu_0 H_P = \frac{\sqrt{2}\Delta}{g\mu_B}
The maximum magnetic field at which superconductivity can still exist is determined by the energy gap Δ and the effective g-factor.
Scientists
Wolfgang PauliEnrico FermiPaul DiracSubrahmanyan ChandrasekharLeo EsakiFelix Bloch
Concepts
g factor flux quantization superconductivity dome magnetic superconductivity superfluid stiffness magnetic flux quantum proximity effect critical current thin film properties conductance quantum confinement thin film superconductivity