Dynamical correlations in a glass former with randomly pinned particles

Area of Science:

• Condensed Matter Physics
• Statistical Mechanics
• Materials Science

Background:

• Glass-forming fluids exhibit complex dynamics near the glass transition.
• Dynamical heterogeneity, characterized by regions of varying relaxation times, is a key feature of these systems.
• Understanding the role of pinning in these dynamics is crucial for materials design.

Purpose of the Study:

• To investigate the impact of random particle pinning on dynamically heterogeneous relaxation in a model glass-forming fluid.
• To quantify the length scale associated with dynamical heterogeneity using four-point dynamical correlations.
• To assess how pinning affects both relaxation times and heterogeneity length scales.

Main Methods:

• Studied a model glass-forming fluid with randomly pinned particles.
• Analyzed four-point dynamical correlations in real space.
• Extracted the length scale characterizing dynamical heterogeneity.

Main Results:

• Pinning increased the system's relaxation time by up to two orders of magnitude.
• There was minimal increase in the four-point correlation length.
• The strength of four-point correlations remained largely unchanged by pinning.

Conclusions:

• Random pinning significantly slows dynamics without altering the intrinsic length scale of heterogeneity.
• These findings challenge some theoretical assumptions about the glass transition.
• The study provides insights into the relationship between dynamics and structure in disordered systems.