A Glimpse Of Silica In Motion

The structure of silica glass has been something of a mystery to scientists. Because of the disordered, amorphous nature of the material, researchers can’t construct a picture of its atoms by using X-ray crystallography as they can with bulk crystals. Instead, an international team led by David A. Muller of Cornell University and Ute Kaiser of Germany’s University of Ulm devised a high-resolution transmission electron microscopy (TEM) method to get an atomic-scale glimpse of this material in motion and used it to study sheets of glass just two atoms thick (Science 2013, DOI: 10.1126/science.1242248). With that technique, the researchers recorded images of the glass as it deformed upon changing from solid to liquid. The TEM images and video reveal “a complex dance” of silicon and oxygen atoms, according to the team. Ring structures open and close. Atoms swap places. The results will likely help scientists create a better picture of the atom dynamics in amorphous materials, which are ubiquitous. Silica glass, for example, can be found in semiconductors and optical fibers.