Criticality of relaxation in dislocation systems

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Physics

Background:

• Dislocation systems are crucial in materials science, influencing mechanical properties.
• Understanding relaxation processes is key to predicting material behavior under stress.
• Previous studies often focused on specific models, lacking a unified explanation for generic features.

Purpose of the Study:

• To investigate the generic relaxation processes in dislocation systems.
• To identify the underlying mechanisms responsible for observed power-law decays.
• To explore the connection between dislocation dynamics and phenomena like criticality and glassy behavior.

Main Methods:

• Employed two-dimensional dynamical simulations to model dislocation systems.
• Studied three distinct physical scenarios to ensure generality of findings.
• Analyzed physical quantities for power-law decay behavior and scaling properties.

Main Results:

• Identified power-law decays in various physical quantities across different scenarios.
• Established that these decays stem from the scaling property of the dislocation velocity distribution.
• Observed scaling breakdown at a system-size-dependent cutoff time.

Conclusions:

• The relaxation dynamics are governed by an underlying scaling property, not intrinsic relaxation times.
• Criticality is a ubiquitous feature in the studied dislocation systems.
• Quenched disorder in slip plane positions is identified as the cause of glassy-like behavior.