Amorphous materials, also known as non-crystalline materials, are characterized by their lack of a regular, repeating atomic structure. This makes them very different from crystalline materials, such as metals and salts, which have highly ordered atomic arrangements. Although amorphous materials are all around us, from the glass in our windows to the polymers in our plastics, we still don't fully understand how their atoms are packed together.
The researchers used a newly developed 3D imaging technique called scanning transmission electron microscopy (STEM) tomography to take pictures of individual atoms in an amorphous material. In this technique, a beam of high-energy electrons is focused onto a thin film of the material, and the resulting scattered electrons are used to reconstruct a 3D image of the atomic arrangements.
"The challenge with these types of materials is that we often don't know their crystal structure, so we need a method that allows us to determine the 3D distribution of atoms within the material," explains Professor Hanbin Zhang, lead author of the study. "STEM tomography allows us to do just that."
Using this technique, the researchers were able to identify two distinct types of atomic arrangements in the amorphous material they studied. One type of arrangement was characterized by dense clusters of atoms, while the other was more open and diffuse. The researchers believe that these two types of arrangements may be responsible for the material's unique properties, such as its high strength and flexibility.
The researchers say that their work could have far-reaching implications for our understanding of the structure of a wide variety of amorphous materials. This could lead to the development of new materials with improved properties for a variety of applications, such as glass, metal alloys, and polymers.
