Calculation of elastic constants of embedded-atom-model potentials in the NVT ensemble

Area of Science:

• Materials Science
• Computational Physics
• Condensed Matter Physics

Background:

• Calculating elastic constants is crucial for understanding material properties.
• Traditional methods like explicit deformation require multiple simulations under varying conditions.
• Molecular dynamics (MD) offers a potential avenue for more efficient calculations.

Purpose of the Study:

• To detail a method for calculating elastic constants using molecular dynamics (MD) in the NVT ensemble.
• To demonstrate the accuracy and efficiency of this MD-based approach.
• To explore its applicability in calculating local elastic constants and calibrating interatomic potentials.

Main Methods:

• Utilized molecular dynamics (MD) simulations within the NVT ensemble.
• Employed a realistic many-body embedded-atom-model (EAM) potential.
• Calculated the elastic tensor in a single simulation, analyzing convergence with time steps and particle count.

Main Results:

• The NVT MD simulation method provides robust and accurate elastic tensor calculations.
• The method converges rapidly, requiring minimal time steps and particles.
• Demonstrated successful application to calculate elastic constants for copper (0-1000 K), aligning with potential calibration values.

Conclusions:

• The presented NVT MD method is a fast and accurate alternative to explicit deformation for elastic constant calculation.
• Highlights applicability for local elastic constants in nonhomogeneous materials and interatomic potential calibration.
• Provides insights into temperature-dependent contributions (Born, stress fluctuation, ideal gas terms) to elastic constants.