Polar nanoregions and reentrant-like ferroelectric behavior in SrTiO3
Abstract
Recent real-space imaging in quantum paraelectric SrTiO3 [Nature 656, 54 (2026)] reveals that local polar textures do not continuously grow upon cooling, but reach a maximum intensity at intermediate temperatures around 60-65 K and weaken again toward the quantum paraelectric ground state. Such a reentrant-like weakening of local polar textures challenges the conventional paradigm in which ordering tendencies generally continue to strengthen as temperature decreases. Here we employ a self-consistent phase-field theory showing that this anomalous behavior naturally arises from the coupling between intrinsic polar and antiferrodistortiv (AFD) fluctuations. We demonstrate that the flexoelectric-like coupling strongly hybridizes the polar and AFD modes. As the uncoupled polar and AFD modes cross near 52 K, their hybridization is maximized, driving the lower hybridized branch to develop a minimum on a finite-wave-vector shell. This finite-q softening triggers a Brazovskii-type instability, strongly enhancing polarization correlations and producing nanoscale polar textures. Away from the crossing temperature, the two modes become increasingly detuned, weakening their hybridization and the associated finite-q softening. These results reaveal the origin of the formation of polar nanoregions in SrTiO3, naturally explaining the unexpected confinement to an intermediate-temperature window and providing a mechanism beyond the quantum-fluctuation-based interpretation suggested by experiment. Furthermore, we predict an unconventional reentrant-like sequence in weakly strained SrTiO3, evolving from ferroelectric to paraelectric, polar-nanoregion, and eventually paraelectric regimes upon heating from zero temperature.
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BibTeX
@misc{sun2026polar,
title = {{Polar nanoregions and reentrant-like ferroelectric behavior in SrTiO$_3$}},
author = {Yuan-Jie Sun and Fei Yang and Long-Qing Chen},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.01446},
eprint = {2609.01446},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.01446},
}
RIS
TY - UNPB
TI - Polar nanoregions and reentrant-like ferroelectric behavior in SrTiO_3
AU - Yuan-Jie Sun
AU - Fei Yang
AU - Long-Qing Chen
PY - 2026
DA - 2026/09/21
PB - arXiv
DO - 10.48550/arxiv.2609.01446
UR - https://arxiv.org/abs/2609.01446
AB - Recent real-space imaging in quantum paraelectric SrTiO_3 [Nature 656, 54 (2026)] reveals that local polar textures do not continuously grow upon cooling, but reach a maximum intensity at intermediate temperatures around 60-65 K and weaken again toward the quantum paraelectric ground state. Such a reentrant-like weakening of local polar textures challenges the conventional paradigm in which ordering tendencies generally continue to strengthen as temperature decreases. Here we employ a self-consistent phase-field theory showing that this anomalous behavior naturally arises from the coupling between intrinsic polar and antiferrodistortiv (AFD) fluctuations. We demonstrate that the flexoelectric-like coupling strongly hybridizes the polar and AFD modes. As the uncoupled polar and AFD modes cross near 52 K, their hybridization is maximized, driving the lower hybridized branch to develop a minimum on a finite-wave-vector shell. This finite-q softening triggers a Brazovskii-type instability, strongly enhancing polarization correlations and producing nanoscale polar textures. Away from the crossing temperature, the two modes become increasingly detuned, weakening their hybridization and the associated finite-q softening. These results reaveal the origin of the formation of polar nanoregions in SrTiO_3, naturally explaining the unexpected confinement to an intermediate-temperature window and providing a mechanism beyond the quantum-fluctuation-based interpretation suggested by experiment. Furthermore, we predict an unconventional reentrant-like sequence in weakly strained SrTiO_3, evolving from ferroelectric to paraelectric, polar-nanoregion, and eventually paraelectric regimes upon heating from zero temperature.
ER -