Emergent Berezinskii-Kosterlitz-Thouless Phase in Low-Dimensional Ferroelectrics

Y. Nahas (1) , S. Prokhorenko (1, 2) , I. Kornev (3) , L. Bellaiche (4, 1)

1 University of Arkansas [Fayetteville]
2 Q MAT CESAM, Univ Liege, Theoret Mat Phys, Liège
3 SPMS - Laboratoire Structures, Propriétés et Modélisation des solides
4 Department of Physics Department [Fayetteville]

Using first-principles-based simulations merging an effective Hamiltonian scheme with scaling, symmetry, and topological arguments, we find that an overlooked Berezinskii-Kosterlitz-Thouless (BKT) phase sustained by quasicontinuous symmetry emerges between the ferroelectric phase and the paraelectric one of BaTiO3 ultrathin film, being under tensile strain. Not only do these results provide an extension of BKT physics to the field of ferroelectrics, but they also unveil their nontrivial critical behavior in low dimensions.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Y. Nahas, S. Prokhorenko, I. Kornev, L. Bellaiche. Emergent Berezinskii-Kosterlitz-Thouless Phase in Low-Dimensional Ferroelectrics. Physical Review Letters, 2017, 119 (11), ⟨10.1103/PhysRevLett.119.117601⟩. ⟨hal-01614233⟩