Control of ferroelectric domain wall dynamics by point defects: Insights from ab initio based simulations

This repository contains the simulation data for 180° domain wall (DW) in tetragonal BaTiO3 using an ab initio derived coarse-grained molecular dynamics package Feram.

These data are supplementary for an associated publication and can be viewed with visualization softwares (e.g. OVITO) and scripts in a RUB Gitlab repository.

File formats

All files (1: data.avg, 2: *.hl, 3: *.coord, 4: *.dump) use the space-separated format except DW_summary.csv which uses the semicolon-separated format.

(1) data.avg columns:T: temperature in KelvinEx Ey Ez: external_E_field along x,y,z in V/Angstrom.exx eyy ezz eyz ezx exy: strain tensorux uy uz: dipole displacements in Angstromuxux uyuy uzuz uyuz uzux uxuy: cross-terms of dipole displacements in Angstrom^2dk: dipo_kinetic in eV/u.c.lr: long_range in eV/u.c.dEf: dipole_E_field in V/Angstromunhar: unharmonic in eV/u.c.s_ho: homo_strain in eV/u.c.c_ho: homo_coupling in eV/u.c.s_inho: inho_strain in eV/u.c.c_inho: inho_coupling in eV/u.c.etot: total energy in eV/u.c.HNP: H_Nose_Poincare in eV/u.c.e2: e2dkt: dipo_kinetic_true in eV/u.c.ak: acuou_kinetic in eV/u.c.sr: short_range in eV/u.c.mod: inho_modulation in eV/u.c.px py pz: px py pzppx ppy ppz ppyz ppzx ppxy: ppx ppy ppz ppyz ppzx ppxymx my mz: , , in Angstromamx amy amz: <|ux|>, <|uy|>, <|uz|> in Angstrom

(2) *.hl columns:step: timestepT: temperature in KelvinEx Ey Ez: external_E_field in V/Angstrom exx eyy ezz eyz ezx exy: strain tensorux uy uz: dipole displacements in Angstrom

(3) *.coord columns:ix iy iz: coordinatesdipoRx dipoRy dipoRz: dipole displacements in AngstromdipoPx dipoPy dipoPz: ppx ppy ppz dVddix dVddiy dVddiz: ddx ddy ddzacouRx acouRy acouRz: arx ary arzacouPx acouPy acouPz: apx apy apz

(4) dump* columns (dump files are converted from *.coord files)ITEM: TIMESTEPITEM: NUMBER OF ATOMSITEM: BOX BOUNDS pp pp pp ITEM: ATOMS id type v_mod xu yu zu fx fy fz 1 0 (ps.: type, v_mod columns are not used in this study.)

(5) DW_summary.csv : (the 1st line is the header)system (str): simulation system temp (int): temperature in Kelvinlr (str): L/R for left/right DWdv (int): linear division of DW area in u.c.ind (tuple(2)): (i, j) index of sub-DWsdefects (dict): x, y, z coordinates of defectsxdw (list): positions of sub-DWsvdw (list): velocities of sub-DWsrgh (list): roughness of sub-DWs

Folder structure & naming

0-preliminary (single-domain)└─0-preliminary    └─0-size-convergence         └─0-36x36x36|1-48x48x48|2-60x60x60             └─1-cooling|2-heating                 └─logfile1-T180DW (tetragonal 180° DW)├─a1-field_hysteresis│  └─0-pristine : (single-domain)│       └─hl_260 : (temperature at 260K)│          ├─logfile_l│          └─logfile_r├─3-rand3d : (defects in 3D)│  ├─1-PuNd_0.5_1_2%|3-PuNd_1%_dd│  │  └─240K|260K|280K│  │     └─dir_ana_dd_pt_s0_100kVocm : =0.09, 0.11, 0.15 (Ang); =0.5, 1.0, 2.0 (% in 3D)│  │        └─logfile_ramp_ : i=0--9 (10 independent simulations)│  └─s1-1%_nofield : (field removal for c=1.0 and i=0)│      ├─restart│      └─260K│          └─dir_ana_dd0.09_1.0pt_s0_0kVocm │              └─logfile_ramp_0├─4-layers : (defect plane)│  ├─1-1L_1_2_4_8_10%|2-1L_2.5_3.0_3.5%|5-1L_1_2_2.5_3_3.5_4|7-1L_5_6_7% : (1-layer)│  ├─3-hLz_1_2_4_6_8%|4-hLy_1_2_4_6_8% : (z/y-half-layer)│  │  └─240K|260K|280K│  │      └─dir_ana_dd-0.09_r_s_100kVocm : =1, 2, 2.5, 3, 3.5, 4, 5, 6, ...  (% in 2D); =0, 1 (2 distrs.)│  │          └─logfile_ramp_ : i=0--4 (5 independent simulations)│  ├─8-1L_slit_zd1_2_3_4_5|9-1L-slit_yd38_39_40_41 : (z/y-slit)│  │  └─260K│  │      └─dir_ana_dd-0.09_d_100kVocm : =1, 2, 3, 4, 5 or 38, 39, 40, 41 (u.c.)│  │          └─logfile_ramp_ : i=0--9 (10 independent simulations)│  └─s1-1L_3.5%_nofield : (field removal for r=3.5, s=0, and i=0)│      ├─restart│      ├─260K_100ps│      │  └─dir_ana_dd-0.09_r3.50_s0_0kVocm│      │      └─logfile_ramp_0│      └─260K_90ps│          └─dir_ana_dd-0.09_r3.50_s0_0kVocm│              └─logfile_ramp_0└─pristine    └─240K|260K|280K        └─dir_ana_pt_r0.00_s0_kVocm : =0, 75, 100, 150 (kV/cm)            └─logfile_ramp_0