Richard Zallen, a renowned glass scientist, once stated that the atomic structure of an amorphous solid is one of its key mysteries, and structural information must be won with great effort. It is surprising how little is known about this material class. Amorphous materials are difficult to be analyzed by surface science techniques in general. Modern scanning tunneling microscopes combined with the expertise of building up oxide model systems opened-up new perspectives for amorphous materials. Here we have picked the archetypal oxide network former, namely vitreous silica. Besides having analyzed the structure of vitreous silica beforehand, we have now also unveiled the structural transition between a crystalline and a vitreous phase. The occurrence and the connection of structural elements in the transition region has been resolved and explained. This work is of importance for the glass community and addresses crystalline-amorphous interfaces in general. A whole class of tetrahedrally coordinated materials is involved.
Leonid Lichtenstein, Markus Heyde, and Hans-Joachim Freund
The Crystalline–Vitreous Interface in Two Dimensional Silica
Phys. Rev. Lett. 109, 106101 (2012)