Activated sampling in complex materials at finite temperature: the properly obeying probability activation-relaxation...

Area of Science:

• Computational physics
• Materials science
• Statistical mechanics

Background:

• Complex systems dynamics are often governed by activated events.
• Existing simulation methods struggle to efficiently sample conformation space while maintaining thermodynamic accuracy.
• The Activation-Relaxation Technique (ART) offers efficiency but sacrifices thermodynamic correctness.

Purpose of the Study:

• To introduce Properly Obeying Probability ART (POP-ART), an extension of ART.
• To develop a simulation method that correctly samples the thermodynamic ensemble.
• To address the limitations of existing methods in simulating activated events in complex systems.

Main Methods:

• Developed POP-ART, an extension of the Activation-Relaxation Technique.
• Ensured POP-ART obeys detailed balance for thermodynamic accuracy.
• Applied POP-ART to model systems: vacancy and interstitial in crystalline silicon.

Main Results:

• POP-ART correctly recovers thermodynamical weights of accessible states.
• POP-ART demonstrates significantly improved speed compared to molecular dynamics for vacancy simulations below 700 K.
• Validated the method's ability to accurately simulate complex system dynamics.

Conclusions:

• POP-ART provides a thermodynamically consistent and efficient simulation approach.
• This method is particularly advantageous for systems dominated by activated events.
• POP-ART advances the simulation of materials properties, such as point defects in silicon.