Topological Defects in Hexagonal Manganites: Inner
Structure and Emergent Electrostatics
Megan
E. Holtz
Konstantin Shapovalov
Julia A. Mundy
Celesta S. Chang
Zewu Yan
Edith Bourret
David A. Muller
Dennis Meier
Andrés Cano
10.1021/acs.nanolett.7b01288.s001
https://acs.figshare.com/articles/journal_contribution/Topological_Defects_in_Hexagonal_Manganites_Inner_Structure_and_Emergent_Electrostatics/5402413
Diverse
topological defects arise in hexagonal manganites, such
as ferroelectric vortices, as well as neutral and charged domain walls.
The topological defects are intriguing because their low symmetry
enables unusual couplings between structural, charge, and spin degrees
of freedom, holding great potential for novel types of functional
2D and 1D systems. Despite the considerable advances in analyzing
the different topological defects in hexagonal manganites, the understanding
of their key intrinsic properties is still rather limited and disconnected.
In particular, a rapidly increasing number of structural variants
is reported without clarifying their relation, leading to a zoo of
seemingly unrelated topological textures. Here, we combine picometer-precise
scanning-transmission-electron microscopy with Landau theory modeling
to clarify the inner structure of topological defects in Er<sub>1–<i>x</i></sub>Zr<sub><i>x</i></sub>MnO<sub>3</sub>. By
performing a comprehensive parametrization of the inner atomic defect
structure, we demonstrate that one primary length scale drives the
morphology of both vortices and domain walls. Our findings lead to
a unifying general picture of this type of structural topological
defects. We further derive novel fundamental and universal properties,
such as unusual bound-charge distributions and electrostatics at the
ferroelectric vortex cores with emergent U(1) symmetry.
2017-09-05 00:00:00
topological defects
Landau theory modeling
1 D systems
Emergent Electrostatics Diverse topological defects
length scale drives
picometer-precise scanning-transmission-electron microscopy
domain walls