Open AccessHyperuniformity and static structure factor of amorphous silicon in the infinite-wavelength limit
Author(s) -
Devilal Dahal,
Raymond AttaFynn,
Stephen R. Elliott,
Parthapratim Biswas
Publication year - 2019
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1252/1/012003
Subject(s) - structure factor , extrapolation , silicon , amorphous solid , amorphous silicon , scattering , limit (mathematics) , materials science , condensed matter physics , range (aeronautics) , molecular dynamics , molecular physics , computational physics , statistical physics , physics , crystallography , crystalline silicon , optics , mathematics , chemistry , quantum mechanics , mathematical analysis , metallurgy , composite material
The static structure factor of amorphous silicon ( a -Si) models, containing 400,000 atoms with a density of 2.25 g⋅cm −3 , has been studied by generating atomistic models using classical molecular-dynamics simulations. The behavior of the structure factor, S ( Q ), in the limit Q → 0, is examined to determine the degree of hyperuniformity in a-Si and is compared with the results with those from earlier simulations and small-angle X-ray scattering experiments. The study suggests that the computed value of the relative variance of the number of atoms at large distances, and hence S ( Q → 0), lies in the range from 0.00736 to 0.00758, which is very close to the experimental value of 0.0076 ± 0.0005, obtained from an extrapolation of transmission X-ray scattering data in the small-angle region. The non-zero value of the structure factor S (0) in a -Si can be attributed to density fluctuations on a very large length scale, which is a characteristic property of the structural and topological ordering of silicon atoms in the amorphous state.