Transitional Band Gaps During Polarization Switching in Wurtzite Ferroelectrics
- 1Rensselaer Polytechnic Institute
- 2Colorado School of Mines
Abstract
The electronic band gap ( E g ) is commonly treated as a static materials property associated with an equilibrium crystal structure. Yet in functional materials whose operation involves field-driven structural transformations, the relevant electronic structure may evolve as the atoms traverse different configurations, with consequences for materials design and device reliability. Wurtzite ferroelectrics provide a compelling setting to examine this idea because polarization reversal requires substantial atomic rearrangement and unusually large electric fields that can approach dielectric breakdown. Here, using first-principles calculations, we track E g along atomistically resolved polarization switching minimum energy pathways in experimentally established Al 1−x Sc x N, Ga 1−x Sc x N, and Al 1−x B x N ferroelectric alloys. As cation-centered tetrahedra rearrange and invert during switching, the band gap decreases substantially relative to the equilibrium polar state, with reductions reaching approximately 30-40% in some compositions. Importantly, the minimum E g does not necessarily coincide with zero polarization or with the highest-energy configuration along the switching pathway, demonstrating that the energetic and electronic structure landscapes do not map trivially onto one another. Extending the analysis to 24 chemically diverse wurtzite compounds reveals transitional E g reductions ranging from negligible to nearly 50%. These results identify the minimum E g sampled along the switching trajectory as an important, material-specific descriptor of electronic robustness. The results also suggest an intrinsic contribution to transient excess conduction during switching and motivate future studies connecting transitional electronic structure to conductive domain walls and memristive behavior in ferroelectrics.
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BibTeX
@misc{brambati2026transitional,
title = {{Transitional Band Gaps During Polarization Switching in Wurtzite Ferroelectrics}},
author = {Alice Brambati and Thi Nguyen and Cheng-Wei Lee and Bhawna Sahni and Geoff L. Brennecka and Prashun Gorai},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15009121/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009121/v1},
note = {CC BY-NC},
}
RIS
TY - UNPB
TI - Transitional Band Gaps During Polarization Switching in Wurtzite Ferroelectrics
AU - Alice Brambati
AU - Thi Nguyen
AU - Cheng-Wei Lee
AU - Bhawna Sahni
AU - Geoff L. Brennecka
AU - Prashun Gorai
PY - 2026
DA - 2026/09/21
PB - ChemRxiv
DO - 10.26434/chemrxiv.15009121/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15009121/v1
AB - The electronic band gap ( E g ) is commonly treated as a static materials property associated with an equilibrium crystal structure. Yet in functional materials whose operation involves field-driven structural transformations, the relevant electronic structure may evolve as the atoms traverse different configurations, with consequences for materials design and device reliability. Wurtzite ferroelectrics provide a compelling setting to examine this idea because polarization reversal requires substantial atomic rearrangement and unusually large electric fields that can approach dielectric breakdown. Here, using first-principles calculations, we track E g along atomistically resolved polarization switching minimum energy pathways in experimentally established Al 1−x Sc x N, Ga 1−x Sc x N, and Al 1−x B x N ferroelectric alloys. As cation-centered tetrahedra rearrange and invert during switching, the band gap decreases substantially relative to the equilibrium polar state, with reductions reaching approximately 30-40% in some compositions. Importantly, the minimum E g does not necessarily coincide with zero polarization or with the highest-energy configuration along the switching pathway, demonstrating that the energetic and electronic structure landscapes do not map trivially onto one another. Extending the analysis to 24 chemically diverse wurtzite compounds reveals transitional E g reductions ranging from negligible to nearly 50%. These results identify the minimum E g sampled along the switching trajectory as an important, material-specific descriptor of electronic robustness. The results also suggest an intrinsic contribution to transient excess conduction during switching and motivate future studies connecting transitional electronic structure to conductive domain walls and memristive behavior in ferroelectrics.
ER -