NEB data from: Revealing the defect-driven ferroelectric mechanisms of aluminum nitride
Data files
May 29, 2026 version files 513.38 MB
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AlN-NEB-vacancy.tar
513.37 MB
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README.md
5.28 KB
Abstract
Wurtzite III-nitride compounds are CMOS-compatible with widespread industrial interest to exercise ferroelectricity, despite their polar structure being highly resistant to polarization reversal. Here, we induce and tune ferroelectric properties in w-AlN via direct-write ion-beam processing, using nanoscale patterned defect engineering as a post-growth alternative to conventional cation substitution. Nanometric piezoresponse spectroscopy of the focused He+ beam patterned defect concentrations in ferroelectric Al0.92B0.08N measures a localized 10x enhancement in effective piezoresponse and 40% reduction in switching barrier. The irradiation-induced point defects convert piezoelectric AlN into a ferroelectric system with site-saturated nucleation and raise the dielectric susceptibility, switched polarization, and effective piezoelectric coefficient. Enhanced defect-lattice interactions in AlN increase carrier conduction and phonon scattering loss but preserve long-range crystallinity. Based on atomistic analysis of nudged elastic band density functional theory calculations and reactive force field simulations, both nitrogen vacancies and defect complexes disrupt bond ordering, facilitating a line-by-line low-barrier switching of pristine AlN.
Dataset DOI: https://doi.org/10.5061/dryad.wwpzgmt0j
Description of the Dataset and File Structure
This dataset contains the DFT NEB calculations used in the paper "Revealing the Defect-Driven Ferroelectric Mechanisms of Aluminum Nitride" https://doi.org/10.1002/adma.202520258. We studied three different atomic switching conditions and how defects affected the energy barrier.
1. Overview
This dataset accompanies the publication:
Behrendt, D.; et al.
Revealing the Defect-Driven Ferroelectric Mechanisms of Aluminum Nitride
Advanced Materials (2025).
https://doi.org/10.1002/adma.202520258
The dataset contains density functional theory (DFT) nudged elastic band (NEB) calculations used to investigate polarization switching pathways in bulk aluminum nitride (AlN) under multiple defect conditions.
The calculations were performed to study how point defects influence ferroelectric switching barriers and polarization reversal mechanisms in wurtzite AlN.
The dataset includes:
- Full NEB calculation directories
- Input and output files for all simulations
- Intermediate NEB image structures
- Energy barrier summary files
- Plotting scripts for visualization of switching pathways
2. Main Archive
File: AlN-NEB-vacancy.tar
This archive contains three separate NEB studies representing different polarization switching mechanisms in bulk AlN:
allflip/wallflip/lineflip/
Each study contains calculations for four different defect configurations:
pure/val/vn/val-on/
3. Switching Pathway Directories
allflip/
NEB calculations in which the polarization of the entire crystal reverses simultaneously.
This pathway represents coherent bulk polarization switching and serves as a reference switching mechanism.
wallflip/
NEB calculations in which a column of atoms reverses polarization along a domain-wall-like configuration.
This pathway models domain-wall-assisted switching processes.
lineflip/
NEB calculations in which a localized column of atoms switches polarization independently from the surrounding crystal.
This configuration was used to investigate localized switching and defect-assisted nucleation behavior.
4. Defect Configuration Directories
Within each switching pathway directory (allflip/, wallflip/, lineflip/), the following defect configurations are included:
pure/
Defect-free aluminum nitride calculations.
val/
Calculations containing an aluminum vacancy defect.
vn/
Calculations containing a nitrogen vacancy defect.
val-on/
Calculations containing an aluminum vacancy paired with a nearby oxygen substitution on a nitrogen lattice site.
This defect complex was studied to evaluate defect-mediated stabilization and modified switching energetics.
5. Structure of Individual Calculation Directories
Each defect directory contains a complete NEB calculation workflow, including:
- Quantum ESPRESSO input files (
*.in) - Quantum ESPRESSO output files (
*.out) - Intermediate NEB image directories
- Relaxed atomic structures
- Energy and convergence information for each image
The included files are sufficient to reproduce the reported NEB switching calculations using Quantum ESPRESSO.
6. Summary and Analysis Files
Within each switching pathway directory:
energies.csvfiles summarize calculated switching barriers and relative energies for the NEB calculationsplot.pyscripts generate plots of the NEB energy profiles from the calculation outputs
Each row of the .csv files corresponds to a specific switching pathway and defect configuration.
7. Computational Methods
All calculations were performed using density functional theory (DFT) and nudged elastic band (NEB) methods implemented in Quantum ESPRESSO.
The NEB method was used to calculate minimum-energy polarization switching pathways between oppositely polarized states.
The workflow includes:
- Structural relaxation
- Intermediate image generation
- NEB optimization
- Extraction of switching energy barriers
8. Software Used
The calculations were performed using:
- Quantum ESPRESSO (DFT and NEB calculations)
https://www.quantum-espresso.org
Additional data analysis and visualization were performed using:
- Python 3.x
9. Reuse Instructions
To reproduce the calculations:
- Install Quantum ESPRESSO with NEB functionality enabled
- Use the included input files and image structures for each switching pathway and defect configuration
- Run NEB calculations using the provided directory structure
- Use the included
plot.pyscripts to reproduce energy profile figures
Users may adapt these workflows to study additional defect configurations or polarization switching mechanisms in wurtzite materials.
10. Access Information
No external datasets were used in this study.
All data included in this archive were generated specifically for this publication.