Topological Defects in Hexagonal Manganites: Inner Structure and Emergent Electrostatics.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Crystallography

Background:

• Hexagonal manganites exhibit diverse topological defects like ferroelectric vortices and domain walls.
• These defects offer potential for novel 2D and 1D functional systems due to unique couplings.
• Understanding intrinsic properties and relationships between defect variants remains limited.

Purpose of the Study:

• To clarify the inner atomic structure of topological defects in Er$_{1-x}$Zr$_{x}$MnO$_{3}$ hexagonal manganites.
• To establish a unifying framework for understanding the morphology of vortices and domain walls.
• To derive fundamental and universal properties of these structural topological defects.

Main Methods:

• Picometer-precise scanning-transmission electron microscopy (STEM) for atomic-level imaging.
• Landau theory modeling to analyze defect structures and properties.
• Comprehensive parametrization of the inner atomic defect structure.

Main Results:

• A single primary length scale governs the morphology of both ferroelectric vortices and domain walls.
• Demonstration of a unifying general picture for structural topological defects in hexagonal manganites.
• Discovery of novel bound-charge distributions and electrostatics at ferroelectric vortex cores with emergent U(1) symmetry.

Conclusions:

• The study provides a unified understanding of topological defects in hexagonal manganites.
• Identified universal properties and emergent U(1) symmetry in ferroelectric vortex cores.
• Findings pave the way for designing novel functional materials based on topological defects.