Some materials behave unexpectedly. They crack differently than expected, or react in ways that are hard to explain. The answer often lies in their atomic structure. Is it neatly arranged, as in a crystal, or disordered, as in glass? Researchers at the University of Twente have now created a material that is both simultaneously. In two directions it is disordered; in the third, perfectly ordered. Their findings have been published in Nature Communications .
In material science, the distinction between crystalline and amorphous has been fundamental for more than a century. Crystals such as salt or diamond have a strictly repeating atomic pattern. Amorphous materials such as glass lack that long-range order. "We use that distinction every day," says Mark Huijben, a researcher at the University of Twente. "But we often assume that order or disorder is a property of the whole material. Our work shows it can also be a matter of direction."
The new material consists of extremely thin layers with no repeating pattern within each layer. Amorphous, in other words. But those layers are stacked on top of one another in a perfectly periodic sequence. Look at the surface of a single layer and you see disorder. Look perpendicular to the stack and you see order across all layers. André ten Elshof draws a comparison with a stack of paper. "Each sheet may be covered in random writing. From above, you see no pattern. But the stack itself is perfectly even. That is what we are seeing here at the atomic scale."
The key question was: how do you prove that no repetition is hidden anywhere? Using an electron microscope, the researchers mapped the positions of individual atoms. To test whether any regular structure was present at a larger scale, they also used X-rays.
A crystal reveals itself through sharp, fixed patterns in the scattering of X-rays. An amorphous material, by contrast, produces diffuse signals with no fixed repetition. In this material, the researchers saw both at once: sharp signals in one direction and diffuse patterns in the other two. "We wanted to be absolutely certain we hadn’t missed any subtle repetition," says ten Elshof. "Now we can show that the absence of repetition is genuinely demonstrable."
"For a long time, we thought amorphous and crystalline were two extremes," says Huijben. "This material shows they can coexist in a single structure." This challenges the classic dichotomy between order and chaos. The boundary turns out not to be a fixed dividing line, but a matter of perspective. "Many new materials have properties that depend on structures sitting between amorphous and crystalline," says ten Elshof. "This insight can help optimise performance for target applications."
Mark Huijben and André ten Elshof are professors in the Faculty of Science and Technology at the University of Twente. Their paper, "Orientation-dependent mutual crystalline and amorphous order in a single phase solid ", has been published in Nature Communications.
10.1038/s41467-026-69359-3
