For the last century, the concept of crystals has been a mainstay of solid-state physics. Crystals are paragons of order; crystalline materials are defined by the repeating patterns their constituent atoms and molecules make.
Now physicists at the University of Pennsylvania and the University of Chicago have evidence that a new concept should undergird our understanding of most materials: the anticrystal, a theoretical solid that is completely disordered.
Their work suggests that, when trying to understand a real material's mechanical properties, scientists would be better served in many cases by starting with the framework of the anticrystal and adding order, rather than starting with a perfect crystal and adding disorder. That is because the mechanical properties of even a slightly disordered solid can have more in common with an anticrystal than a perfect crystal.
Understanding these properties is critical for modeling how materials will respond to stress, as well as for designing new materials and predicting their behavior.