We always thought crystals were perfectly repeating patterns of atoms, but it turns out we’ve been wrong this whole time.
March 26, 2026
Original Paper
Breakdown of the periodic potential ansatz in correlated electron systems
arXiv · 2603.24347
The Takeaway
For nearly a century, solid-state physics has been built on the 'periodic potential' rule—the idea that atoms in a crystal repeat like tiles on a floor. This study reveals that in certain metals, the environment is so chaotic that this repeating pattern effectively breaks down, meaning our basic textbooks for modeling materials are fundamentally incomplete.
From the abstract
Our electronic structure theory for crystalline solids is commonly built on the periodic potential assumption $V(\mathbf r)=V(\mathbf r+\mathbf R)$ for every lattice translation $\mathbf R$, enabling Bloch eigenstates, crystal momentum as a good quantum number, and the standard quasiparticle-based description of the behavior of metals. Because the zero-point motion of the ions, however, in correlated electron systems the electronic environment experienced by an itinerant electron is neither stat