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Emergent Berezinskii-Kosterlitz-Thouless Phase in Low-Dimensional Ferroelectrics
Y Nahas1, S Prokhorenko1,2, I Kornev3
1Physics Department and Institute for Nanoscience and Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA.
Physical Review Letters
|September 27, 2017
Summary
An overlooked Berezinskii-Kosterlitz-Thouless (BKT) phase emerges in strained barium titanate ultrathin films. This finding extends BKT physics to ferroelectrics and reveals novel low-dimensional critical behaviors.
Area of Science:
- Condensed matter physics
- Materials science
- Ferroelectricity
Background:
- Barium titanate (BaTiO3) is a crucial ferroelectric material with applications in electronics.
- Understanding phase transitions in ultrathin films is essential for nanoscale device development.
- The Berezinskii-Kosterlitz-Thouless (BKT) phase is a topological phase transition typically observed in 2D systems.
Purpose of the Study:
- To investigate the phase transitions in BaTiO3 ultrathin films under tensile strain.
- To explore the potential emergence of a BKT phase in ferroelectric materials.
- To understand the critical behavior of ferroelectrics in low dimensions.
Main Methods:
- First-principles-based simulations.
- Effective Hamiltonian scheme.
- Analysis of scaling, symmetry, and topological arguments.
Main Results:
- An overlooked BKT phase is identified between the ferroelectric and paraelectric phases of BaTiO3 ultrathin films under tensile strain.
- This BKT phase is sustained by quasicontinuous symmetry.
- The study reveals nontrivial critical behavior in low-dimensional ferroelectrics.
Conclusions:
- The findings extend the understanding of BKT physics to the field of ferroelectrics.
- This research highlights the importance of topological phases in ferroelectric materials.
- New insights into the low-dimensional critical phenomena of BaTiO3 ultrathin films are provided.
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