Distinct signature of local tetrahedral ordering in the scattering function of covalent liquids and glasses.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30838331.
- Also identified by DOI 10.1126/sciadv.aav3194 and PMC identifier 6397023.
- Licence recorded as CC BY-NC.
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Abstract
Tetrahedral amorphous materials such as SiO<sub>2</sub>, GeO<sub>2</sub>, Si, Ge, C, and chalcogenides are extremely important in nature and technology. It is known that covalent bonding favors local tetrahedral order in these materials. However, how to extract information on this structural order from the scattering function has remained elusive. By analyzing the structure of simulated SiO<sub>2</sub> and experimental data of various tetrahedral materials, we show that the lowest wave number peak, known as the first sharp diffraction peak (FSDP), and a few higher wave number ones in the scattering functions come from the characteristic density waves of a single tetrahedral unit. FSDP is thus a direct measure of the tetrahedrality. This finding opens the door for long-awaited experimental access to the characterization of disordered amorphous structures.