Zhuravlyov, Vitaliy | Search NASA

DOE OSTI2023

Finite-size effects in the static structure factor S ( k ) and S ( 0 ) for a two-dimensional Yukawa liquid

Finite-size effects in the static structure factor S(k) are analyzed for an amorphous substance. As the number of particles is reduced, S(0) increases greatly, up to an order of magnitude. Meanwhile, there is a decrease in the height of the first peak S peak. These finite-size effects are modeled accurately by the Binder formula for S(0) and our empirical formula for S peak. Procedures are suggested to correct for finite-size effects in S(k) data and in the hyperuniformity index H ≡ S(0)/S peak. These principles generally apply to S(k) obtained from particle positions in noncrystalline substances. As a result, the amorphous substance we simulate is a two-dimensional liquid, with a soft Yukawa interaction modeling a dusty plasma experiment.

2-dimensional systems↗

DOE OSTI2022

Comparison of the static structure factor at long wavelengths for a dusty plasma liquid and other liquids

Especially small values of the static structure factor S(k) at long wavelengths, i.e., small k, were obtained in an analysis of experimental data, for a two-dimensional dusty plasma in its liquid state. For comparison, an analysis of S(k) data was carried out for many previously published experiments with other liquids. Here, the latter analysis indicates that the magnitude of S(k) at small k is typically in a range 0.02–0.13. In contrast, the corresponding value for a dusty plasma liquid was found to be as small as 0.0139. Another basic finding for the dusty plasma liquid is that S(k) at small k generally increases with temperature, with its lowest value, noted above, occurring near the melting point. Simulations were carried out for the dusty plasma liquid, and their results are generally consistent with the experiment. Since a dusty plasma has a soft interparticle interaction, our findings support earlier theoretical suggestions that a useful design strategy for creating materials having exceptionally low values of S(0), so-called hyperuniform materials, is the use of a condensed material composed of particles that interact softly at their periphery.

2-dimensional systems↗