DFSE

Environment and files information

make the version_0 dictionary to get de.x for DFSE. Copy the whole files into workspace except *.md *.png and uncompiled IM2ODE folefold (use de.x - the compiled file).

Environment

conda create -n DFSE python=3.8
conda activate DFSE
pip install pymatgen==2023.8.10 phonopy==2.30.0

Also, vaspkit is required, with setting of POTCAR path, to help DFSE update POTCAR during first principle calculation. We highly recommand to use DFSE in a high-performance cluster, with vaspkit tools, VASP DFT software and gcc >= 12.1.0. If running 2D materials better use a fix c version VASP or add OPTCELL file if VASP version = 6.x

Files information

• de.x -- compiled from IM²ODE package
• python scripts

| Scripts | Function | | :------ | :------ | | ferroelectric_search.py | 1. generate centrosymmetric phases| | | 2. add perturbation to generate ferroelectric candidates | | | 3. process data | |read_poscar.py| Read POSCAR file| | screening_POSCAR.py | Screening of centrosymmetric phases to ensure varity of structures| |get_POSCAR.py|Verify the symmetric of the structure --bounary problem of two-dimensional layer groups| |export_figures.py|Visualization the searching results| |sampling.py|Use the Latin hyperparameters method to sample the high dimension chemical space to obtain the initial structures|

• test.sh -- bash script for main program
• INCAR_1 INCAR_2 INCAR_3 INCAR_4 -- several INCAR_* files for vasp running

| INCAR_* | Function | | :------ | :------ | | INCAR_1 | relax centrosymmetric phases| | INCAR_2 | static calucation for centrosymmetric phases and ferroelectrics candidates | | INCAR_3 | Berry phase for polarization value | | INCAR_4 | relax ferroelectrics candidates|

• POTCAR for DFT

change the parameters in test.sh for you own system

running environment parameters( Slurm & linux )

#!/bin/sh
ulimit -s unlimited
chmod 777 *

pick_up="T" #change T or F to make pick up for previous running DFSE
# Output files
results_file="./results.dat"
log_file="./run.log"
num_parallel=24    # Number of parallel processes
IM2ODE_runtime=60
Perturbation_times=2
MAX_LOOPS=5 #for sturcture relaxzation
MAX_TIME1=7200 #for one time vasp max running time in second when relax the reference phase
MAX_TIME2=12800 #for  one time vasp max running time in second when relax the ferroelectric candidates
#please change VASP_COMMAND for your environment
VASP_COMMAND="mpirun -np 24 /opt/vasp.5.4.4/bin/vasp_std"

IM²ODE running parameters

# Ranges for the variables
DIS_min=1.2   #Atoms distance
DIS_max=3.0
Volumn_min=60.0    #volume for 3D structures
Volumn_max=70.0
AREA_min=24.0     #area for 2D structures
AREA_max=27.0
LAYER_HEIGHT_min=5.0    #layer height for 2D sturctures
LAYER_HEIGHT_max=7.0
Atoms_type=3

### basic information for searching
SystemName=TiPbO3
NumberOfSpecies=3
NumberOfElements=1 1 3
NameOfElements=Ti Pb O
DistanceOfAtom=
$formatted_DIS_lines
Population=10
MaxStep=1
Volumn=$Volume

#2D system setting 
Q2D=F
vacuum_layer=15
Area=$AREA
Layer_height=$LAYER_HEIGHT

#polarization switch and choose crystal system for initial strcuture generation

polarization_3d = .TRUE.
crystal_system_3d = 2 3 4 5 6 7 
crystal_system_count_3d = 6

#polarization_2d = .TRUE.
#crystal_system_2d = 1 2 3 4 5 6  
#crystal_system_count_2d = 6

#FQFE switch and perturbation coefficient
FQFE=.FALSE.
COEFFICIENT=0.06

submit the test.sh and waiting for program running

running results

The searching results is saved in ferro_search_results filefold and the detailed information is recorded in results.info file. Also, the results would be visualized and can be check in scatter_plot.html

citation

If you are using our method or code, please consider citing our work:

@article{chen2025dfse,
  title={DFSE: Inverse Design of Ferroelectrics from Spatial Symmetry Breaking Evolution},
  author={Chen, Lei and Liu, Bang and Guo, Zhixin and Duan, Xiangmei and Fang, Guoyong and Zheng, Yi-Feng and Fang, Haiping and Zhang, Yue-Yu},
  journal={Journal of Chemical Theory and Computation},
  year={2025},
  publisher={ACS Publications},
  doi={10.1021/acs.jctc.5c00333}
}