Structural Commonalities in Amorphous Elemental Materials
In the In recent times, the research community has explored diverse structures and novel fabrication methods for amorphous solids. This work investigates structural trends among different classes of amorphous materials to identify universal commonalities and fundamental differences. It is found that amorphous semiconductors exhibit similar Pair Distribution Functions (PDFs), characteristic of their underlying network-forming nature. On the other hand, amorphous metallic systems also display internally consistent PDF profiles, but different from those of the semiconducting materials. A comparative analysis of short-range and medium-range order reveals that while semiconductor structures feature a well-isolated first peak, with a zero-intensity region between the first and second peaks, metallic systems maintain a significant non-zero value between the first and second peaks. Furthermore, the second peak in metallic systems is bimodal, featuring a distinct elephant-like profile. Amorphous semi-metals display a still different profile, and the PDFs for Bi, for example, are similar to those for As and Sb. To deepen this structural comparison, we have incorporated amorphous Plane Angle Distributions (PADs), providing a more complete perspective on the local geometry. We introduce a renormalization approach that uses the positions of the first peaks in the PDFs to quantify these structural coincidences and discuss the implications.