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Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals
Published on: August 15, 2018
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Switchable Electric Dipole from Polaron Localization in Dielectric Crystals
Kazuki Morita1, Yu Kumagai2, Fumiyasu Oba2,3
1Department of Materials, Imperial College London, London SW7 2AZ, United Kingdom.
Physical Review Letters
|July 16, 2022
Summary
Donor doping in Sr3Ti2O7 crystals creates a localized dipole, exhibiting ferroelectriclike behavior. This phenomenon, distinct from conventional polarization, arises from bound polarons and double-well potentials.
Area of Science:
- Solid State Physics
- Materials Science
- Crystallography
Background:
- Ferroelectricity in crystals typically involves ion displacement or polar unit rotation.
- Understanding novel ferroelectric mechanisms is crucial for advanced materials development.
Purpose of the Study:
- To investigate the ferroelectriclike behavior induced by donor doping in Sr3Ti2O7.
- To characterize the nature and properties of the dipole and bound polaron formed.
Main Methods:
- Berry phase analysis was employed to predict dipole moments.
- Theoretical modeling explored the influence of doping density and Hubbard U interaction.
Main Results:
- A dipole of 6.15 Debye was predicted in the Ruddlesden-Popper phase of Sr3Ti2O7.
- A stable double-well potential was observed, persisting at high doping densities.
- The defect state transitioned between metallic, 2D polaron, and 0D polaron based on Hubbard U.
Conclusions:
- Donor doping in Sr3Ti2O7 can induce localized ferroelectriclike behavior.
- This behavior is attributed to bound polarons and double-well potentials, distinct from spontaneous lattice polarization.
- The findings offer insights into novel mechanisms for ferroelectricity in doped oxides.
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