Dynamical heterogeneity in a highly supercooled liquid: Consistent calculations of correlation length, intensity, and lifetime

作者：Mizuno Hideyuki^*; Yamamoto Ryoichi

来源：Physical Review E, 2011, 84(1): 011506.

DOI：10.1103/PhysRevE.84.011506

We have investigated dynamical heterogeneity in a highly supercooled liquid using molecular-dynamics simulations in three dimensions. Dynamical heterogeneity can be characterized by three quantities: correlation length xi(4), ntensity chi(4), and lifetime tau(hetero). We evaluated all three quantities consistently from a single order parameter. In a previous study [H. Mizuno and R. Yamamoto, Phys. Rev. E 82, 030501(R) (2010)], we examined the lifetime tau(hetero)(t) in two time intervals t = tau(alpha) and tau(ngp), where tau(alpha) is the alpha-relaxation time and tau(ngp) is the time at which the non-Gaussian parameter of the Van Hove self-correlation function is maximized. In the present study, in addition to the lifetime tau(hetero)(t), we evaluated the correlation length xi(4)(t) and the intensity chi(4)(t) from the same order parameter used for the lifetime tau(hetero)(t). We found that as the temperature decreases, the lifetime tau(hetero)(t) grows dramatically, whereas the correlation length xi(4)(t) and the intensity chi(4)(t) increase slowly compared to tau(hetero)(t) or plateaus. Furthermore, we investigated the lifetime tau(hetero)(t) in more detail. We examined the time-interval dependence of the lifetime tau(hetero)(t) and found that as the time interval t increases, tau(hetero)(t) monotonically becomes longer and plateaus at the relaxation time of the two-point density correlation function. At the large time intervals for which tau(hetero)(t) plateaus, the heterogeneous dynamics migrate in space with a diffusion mechanism, such as the particle density.

• 出版日期2011-7-27