Dimensionality-induced change in topological order in multiferroic oxide superlattices

TL;DR

This study investigates how reducing the thickness of multiferroic oxide superlattices induces a transition in topological order, revealing new domain wall behaviors and symmetry changes due to dimensional confinement.

Contribution

It demonstrates the impact of dimensional confinement on topological defects and symmetry in ferroelectric superlattices, highlighting novel phase transitions.

Findings

Thickness-dependent transition from neutral to charged domain walls

Emergence of fractional vortices in thin layers

Symmetry reduction from P63cm to P3c1

Abstract

We construct ferroelectric (LuFeO3)m/(LuFe2O4) superlattices with varying index m to study the effect of confinement on topological defects. We observe a thickness-dependent transition from neutral to charged domain walls and the emergence of fractional vortices. In thin LuFeO3 layers, the volume fraction of domain walls grows, lowering the symmetry from P63cm to P3c1 before reaching the non-polar P63/mmc state, analogous to the high-temperature ferroelectric to paraelectric transition. Our study shows how dimensional confinement stabilizes textures beyond those in bulk ferroelectric systems.