title: Unveiling Dimensionality Dependence of Glassy Dynamics: 2D Infinite Fluctuation Eclipses Inherent Structural Relaxation.
abstract: By using large-scale molecular dynamics simulations, the dynamics of two-dimensional (2D) supercooled liquids turns out to be dependent on the system size, while the size dependence is not pronounced in three-dimensional (3D) systems. It is demonstrated that the strong system-size effect in 2D amorphous systems originates from the enhanced fluctuations at long wavelengths which are similar to those of 2D crystal phonons. This observation is further supported by the frequency dependence of the vibrational density of states, consisting of the Debye approximation in the low-wave-number limit. However, the system-size effect in the intermediate scattering function becomes negligible when the length scale is larger than the vibrational amplitude. This suggests that the finite-size effect in a 2D system is transient and also that the structural relaxation itself is not fundamentally different from that in a 3D system. In fact, the dynamic correlation lengths estimated from the bond-breakage function, which do not suffer from those enhanced fluctuations, are not size dependent in either 2D or 3D systems.
authors.affiliation: Institute for Solid State Physics, University of Tokyo, Chiba 277-8581, Japan.|Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Hayato
authors.initials: H
authors.lastname: Shiba
authors.affiliation: Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Yamada
authors.affiliation: Department of Physics, Nagoya University, Nagoya 464-8602, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kawasaki
authors.affiliation: Department of Physics, Niigata University, Niigata 950-2181, Japan.|Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan.
authors.forename: Kang
authors.initials: K
authors.lastname: Kim