Absence of High-Pressure Ground-State Reentrant Ferroelectricity in PbTiO3
We study ferroelectricity in the classic perovskite ferroelectric PbTiO3 to high pressures with density functional theory (DFT) and experimental diamond-anvil techniques. We use second harmonic generation spectroscopy to detect lack of inversion symmetry. Consistent with early understanding and experiments, we find that ferroelectricity disappears at moderate pressures. However, DFT computations show that the disappearance arises from the overtaking of zone boundary instabilities, and not from the squeezing out of the off-centering ferroelectric displacements with pressure, as previously thought. Moreover, at high pressures the distorted perovskite phases are metastable with respect to a new dense centrosymmetric postperovskite phase with P21/m symmetry and 8-coordinated Ti, which becomes stable at about 70 GPa.
- Research Organization:
- University of Illinois, Chicago, IL (United States)
- Sponsoring Organization:
- U.S. Office of Naval Research; USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
- Grant/Contract Number:
- AC02-06CH11357; NA0003975; NA0004153
- OSTI ID:
- 2507321
- Journal Information:
- Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 23 Vol. 133; ISSN 0031-9007
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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