Polar discontinuity screening by charge disproportionation in ferroelectric-nickelate superlattices
Abstract
We use density functional theory (DFT) to demonstrate rearrangement of charge disproportionation as a new mechanism for screening polar discontinuities at heterointerfaces. We focus on SmNiO3, a III-III perovskite characterized by an insulating ground state that originates from disproportionation of the electrons at the Ni sites. When interfaced with ferroelectric, II-IV perovskite BaTiO3, this system can display a polar discontinuity whose magnitude is determined by the nature of the interface (NiO2-BaO or SmO-TiO2) and the orientation of the BaTiO3 spontaneous polarization. In the orientation maximizing the interface charge, SmNiO3 compensates by transferring 1 e/f.u. between the two interfaces and modifying the disproportionation sequence from Ni4+/Ni2+ to Ni2+/Ni2+ at the SmO-TiO2 interface and to Ni4+/Ni4+ at the NiO2-BaO interface. While this mechanism is potentially universal in all perovskites exhibiting charge disproportionation, our formal analysis of BiNiO3/BaTiO3 superlattices suggests that larger polar discontinuities may need more complex disproportionation patterns for screening.
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BibTeX
@misc{simmen2026polar,
title = {{Polar discontinuity screening by charge disproportionation in ferroelectric-nickelate superlattices}},
author = {Edith Simmen and Jonathan Amara and Philippe Ghosez and Nicola A. Spaldin},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.31375},
eprint = {2609.31375},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.31375},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Polar discontinuity screening by charge disproportionation in ferroelectric-nickelate superlattices
AU - Edith Simmen
AU - Jonathan Amara
AU - Philippe Ghosez
AU - Nicola A. Spaldin
PY - 2026
DA - 2026/09/25
PB - arXiv
DO - 10.48550/arxiv.2609.31375
UR - https://arxiv.org/abs/2609.31375
AB - We use density functional theory (DFT) to demonstrate rearrangement of charge disproportionation as a new mechanism for screening polar discontinuities at heterointerfaces. We focus on SmNiO_3, a III-III perovskite characterized by an insulating ground state that originates from disproportionation of the electrons at the Ni sites. When interfaced with ferroelectric, II-IV perovskite BaTiO_3, this system can display a polar discontinuity whose magnitude is determined by the nature of the interface (NiO_2-BaO or SmO-TiO_2) and the orientation of the BaTiO_3 spontaneous polarization. In the orientation maximizing the interface charge, SmNiO_3 compensates by transferring 1 e/f.u. between the two interfaces and modifying the disproportionation sequence from Ni^4+/Ni^2+ to Ni^2+/Ni^2+ at the SmO-TiO_2 interface and to Ni^4+/Ni^4+ at the NiO_2-BaO interface. While this mechanism is potentially universal in all perovskites exhibiting charge disproportionation, our formal analysis of BiNiO_3/BaTiO_3 superlattices suggests that larger polar discontinuities may need more complex disproportionation patterns for screening.
ER -