Simulation study of spatial–temporal correlation functions in supercooled liquids

Abstract

We perform molecular dynamics simulations on Lennard-Jones binary mixtures of the Kob-Andersen type to investigate the properties of the dynamical heterogeneity near the glass transition. To characterize it, we focus on two types of spatial correlation functions of the direction and mobility fluctuations. Then, we predict the correlation lengths from those correlation functions. Although the correlation length obtained from the direction converges away from the glass transition point, that from the mobility fluctuation increases as the system approaches the glass transition point and has a peak near the glass transition. It suggests that the correlation of the mobility fluctuation plays an important role, more than that of the direction near the glass transition.

Keywords:

• glass and supercooled liquid
• dynamical heterogeneity
• spatial correlation function
• Kob-Andersen model

Acknowledgements

This work was partially supported by Grants-in-Aid for Science Research with No. 18540363 from the Ministry of Education, Culture, Sports, Science and Technology of Japan. Numerical computations for this work were performed on the Origin 2000 machine at the Institute of Fluid Science, Tohoku University.