Quantum paraelectricity and structural phase transitions in strontium titanate beyond density functional theory
Abstract
We demonstrate an approach for calculating temperature-dependent quantum and anharmonic effects with beyond density-functional theory accuracy. By combining machine-learned potentials and the stochastic self-consistent harmonic approximation, we investigate the cubic to tetragonal transition in strontium titanate and show that the paraelectric phase is stabilized by anharmonic quantum fluctuations. We find that a quantitative understanding of the quantum paraelectric behavior requires a higher-level treatment of electronic correlation effects via the random phase approximation. This approach enables detailed studies of emergent properties in strongly anharmonic materials beyond density-functional theory.
- Publication:
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Physical Review Materials
- Pub Date:
- March 2023
- DOI:
- 10.1103/PhysRevMaterials.7.L030801
- arXiv:
- arXiv:2211.09616
- Bibcode:
- 2023PhRvM...7c0801V
- Keywords:
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- Condensed Matter - Materials Science