Criticality in sheared, disordered solids. I. Rate effects in stress and diffusion

Area of Science:

• Condensed matter physics
• Materials science
• Computational physics

Background:

• Sheared disordered solids, like glasses, exhibit complex behaviors under stress.
• Understanding rate effects is crucial for predicting material failure and flow.

Purpose of the Study:

• To investigate rate effects in sheared disordered solids using molecular dynamics simulations.
• To characterize critical behavior, yielding, and particle diffusion in these systems.

Main Methods:

• Molecular dynamics simulations of binary Lennard-Jones glasses in 2D and 3D.
• Analysis of avalanche size distributions, stress-strain curves, and particle diffusion.
• Application of finite-size scaling techniques.

Main Results:

• Systems exhibit critical behavior in the quasistatic regime, with power-law distributed avalanches.
• Flow stress scales with strain rate as a power law (Herschel-Bulkley exponent 1/β).
• Particle diffusion diverges with decreasing rate, explained by a derived scaling theory.

Conclusions:

• The study provides a unified scaling theory for particle diffusion in disordered solids under shear.
• Finite-size scaling reveals key exponents governing material response and correlation lengths.
• Results offer insights into the fundamental physics of yielding and flow in amorphous materials.