Apparent finite-size effects in the dynamics of supercooled liquids

TL;DR

This study uses molecular dynamics simulations to investigate finite-size effects in supercooled liquids, revealing that smaller systems exhibit significantly slower structural relaxation below a critical temperature, despite similar static correlations.

Contribution

It demonstrates that finite-size effects influence the dynamics of supercooled liquids, especially the structural relaxation, which is slower in smaller systems at low temperatures.

Findings

Smaller systems show slower alpha relaxation below T_c.

Static pair correlation functions are unaffected by system size.

Finite-size effects become significant when cooperative motions span the system size.

Abstract

Molecular dynamics simulations are performed for a supercooled simple liquid with changing the system size from N=108 to $10^4$ to examine possible finite-size effects. Although almost no systematic deviation is detected in the static pair correlation functions, it is demonstrated that the structural $\alpha$ relaxation in a small system becomes considerably slower than that in larger systems for temperatures below $T_c$ at which the size of the cooperative particle motions becomes comparable to the unit cell length of the small system. The discrepancy increases with decreasing temperature.