About this Abstract |
Meeting |
2025 TMS Annual Meeting & Exhibition
|
Symposium
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Computational Thermodynamics and Kinetics
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Presentation Title |
Thermodynamic theory of strained thin films of incipient ferroelectric KTaO3
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Author(s) |
Utkarsh Saha |
On-Site Speaker (Planned) |
Utkarsh Saha |
Abstract Scope |
KTaO3 is an incipient ferroelectric with quantum fluctuations stabilizing the soft phonon mode at low temperatures. The influence of external perturbations from strain, dopants or stress can however be used to induce a ferroelectric state. A thermodynamic theory for KTaO3 based on the Landau-Ginzburg-Devonshire theory of ferroelectrics has not been established yet. We formulate a thermodynamic free energy density function for KTaO3 and use it to describe the thermodynamics of KTaO3 single crystals and strained thin films. Using the established Landau coefficients, the calculated electric field-induced polarization and dielectric constant show a good agreement with experimentally measured values. Further, the transition temperatures for thin films under an epitaxial in-plane strain predicted from our model is validated using SHG polarimetry. The stable ferroelectric phases in the analytically constructed temperature-strain phase diagram are identified using the phase-field method. Phase-field is also employed to model domain morphologies at various strain and temperature values. |
Proceedings Inclusion? |
Planned: |