Creep motion of an elastic string in a random potential

Area of Science:

• Condensed Matter Physics
• Soft Matter Physics
• Statistical Mechanics

Background:

• Creep motion describes the slow deformation of materials under stress.
• Understanding creep in disordered systems is crucial for materials science.
• Phenomenological scaling arguments predict creep behavior based on exponents.

Purpose of the Study:

• To investigate the creep motion of an elastic string in a 2D pinning landscape.
• To analyze the velocity-force characteristics and associated creep and roughness exponents.
• To identify different creep regimes based on temperature and disorder strength.

Main Methods:

• Langevin dynamics simulations were employed to model the system.
• Analysis focused on the creep exponent (μ) and roughness exponent (ζ).
• Comparison of simulation results with theoretical predictions.

Main Results:

• Velocity-force characteristics align with phenomenological creep formulas.
• At high temperatures (T > disorder strength), μ ≈ 1/4 and ζ ≈ 2/3, matching the quasi-equilibrium nucleation picture.
• At low temperatures, both μ and ζ increase, indicating a breakdown of the quasi-equilibrium nucleation model.

Conclusions:

• The study validates theoretical creep formulas in certain regimes.
• A distinct low-temperature creep regime emerges, violating established models.
• Findings highlight the complex interplay between temperature, disorder, and creep dynamics in elastic systems.