Interatomic potential test via LAMMPS

DATE: 9 Mar 2023

AUTHOR: lei.zhang@rug.nl

This repository contains the lammps script and python script to calculate the following properties for BCC iron. It can be generalised to test other materials as well. The purpose is to use it on high performance cluster in case that local machine cannot handle the heavy computation, e.g., machine learning potential. With minor modifications, the current workflow can also be used on local machines.

• Energy-Volume curve
• Elastic constants
• Vacancy formation energy
• Surface energies
• Bain path
• Stacking fault (curves) (110)[1-11][-112]
• T-S curve
• Dislocation properties
• Cracks

Prerequisites

1. Installation of LAMMPS with the relevant packages compiled.
2. Installation of PYTHON package: matplotlib, pandas, numpy, scipy.
3. Matlab.

How it works?

The workflow is governed by the bash file (submit.sh) which is a slurm job file. This file copy the lammps inputs and run it, which means that it depends on the system configuration. Thus, one need to specify:

• email address: eaddress (can be skipped).
• load the dependent modules (on cluster):
• give the lammps excutable: LMMP
• specify the path to lammps and python inputs: lmp_inps & pps_python (Those inputs are provided from the repository).
• The DFT reference data if the one wants to generate the plots (the current data is for BCC iron)
• choose the potential: (five potentials are currently available. ACE, GAP, N2P2, ANN, MTP). To customize your own potential, one needs to define it in the script.

After the proper configuration, one is able to perform potential test.

1. copy folder 'pot_testing' and bash file 'submit.sh' to the cluster.
2. Customize the SLURM job submission parameter.
3. make sure the configuration is corrected.
4. run the test by submiting the job script sbatch submit.sh
5. Dislocation and crack calculations require a deep understanding of the code and should be performed separately with care. The users are welcome to contact the author for further consultation.

For testing the dislocation properties.

Currently the workflow does not include the dislocation and cracks benchmark. Everything regarding dislocation and crack calculations are put in the dislocation abd cracks folder, including

• Script to create dislocation using atomsk
• LAMMPS script to crete various dislocations
• K-test for (100) and (110) crack planes For more detials, please refer to the readme file inside dislocaiton and cracks folder.