Alternative origins of polarity in compressively strained SrTiO3-RENiO3 capacitors
Since its original prediction 25 years ago, room-temperature out-of-plane ferroelectricity in compressively strained SrTiO3 remains an ongoing pursuit. In this work, we investigate the structural, electrical, and electromechanical properties of highly strained epitaxial SrTiO3 capacitors with rare earth nickelate electrodes. The SrTiO3 layers experience compressive strains up to −3% and exhibit pronounced tetragonality, comparable to that of bulk PbTiO3. Variable-temperature electrical measurements and room-temperature piezoresponse force microscopy reveal butterfly-shaped capacitance–voltage hysteresis and domain-like electromechanical response typical of ferroelectric materials. However, the overall behavior is inconsistent with a stable ferroelectric state. We therefore propose an alternative mechanism for the observed polarity in our samples based on spatially inhomogeneous internal fields. Our first-principles calculations show that such fields may arise from charge discontinuities between the formally charged NdNiO3 layers and charge-neutral SrTiO3 layers.
Authors
- Panagiotis Koutsogiannis (ORCID: https://orcid.org/0000-0003-3795-6631)
- César Magén (ORCID: https://orcid.org/0000-0002-6761-6171)
- Igor Stolichnov (ORCID: https://orcid.org/0000-0003-0606-231X)
- Pavlo Zubko (ORCID: https://orcid.org/0000-0002-7330-3163)
- Evgenios Stylianidis (ORCID: https://orcid.org/0000-0003-4549-0229)
- Felix Risch (ORCID: https://orcid.org/0000-0001-9525-2259)
- Nicholas C. Bristowe (ORCID: https://orcid.org/0000-0003-1286-8440)
- José A. Pardo
- Jorge Íñiguez (ORCID: https://orcid.org/0000-0001-6435-3604)
- Laura Hechler
- Alexander Lione (ORCID: https://orcid.org/0009-0008-1662-3508)
Institutions
- University of Luxembourg (LU)
- Durham University (GB)
- Universidad de Zaragoza (ES)
- London Centre for Nanotechnology (GB)
- Luxembourg Institute of Science and Technology (LU)
- Instituto de Nanociencia y Materiales de Aragón (ES)
- University College London (GB)
- École Polytechnique Fédérale de Lausanne (CH)
Publication Details
- Journal
- Applied Physics Reviews
- Published
- 2026-11-09
- DOI
- https://doi.org/10.1063/5.0345071
- Citations
- 1
- Primary Topic
- Ferroelectric and Piezoelectric Materials
- Type
- article
- Field-Weighted Citation Impact
- 1.06
Funders
- Durham University
- Fonds National de la Recherche Luxembourg
- London Centre for Nanotechnology
- Engineering and Physical Sciences Research Council