The simple physical arrangement of atoms in a crystal can sabotage superconductivity even if the chemistry stays exactly the same.
April 29, 2026
Original Paper
Bragg-Williams order competes with superconductivity
arXiv · 2604.25843
The Takeaway
Bragg-Williams order describes how atoms are sorted into specific sites within a crystal lattice. Researchers found that this structural ordering independently suppresses the temperature at which a material becomes a superconductor. In one specific material, the transition temperature dropped from 11 Kelvin to 7 Kelvin solely because the atoms were too well-organized. Scientists usually blame electronic or magnetic interference for this drop, but this study proves the furniture layout of the atoms is just as important. Controlling this atomic sorting offers a new way to fine-tune superconductors for future quantum technologies.
From the abstract
Orderings in charge and spin have been extensively studied to unravel their correlation to emergent superconductivity over the past decades. Bragg-Williams order (BWO), a classical structural order parameter describing site occupancy in alloys, has long been speculated to influence superconducting behavior. Yet, its role still remains ambiguous, largely due to the difficulty of isolating BWO from concomitant charge doping or competing electronic instabilities. Here, we establish In2/3PSe3 as a p