Defeating depolarizing fields with artificial flux closure in ultrathin ferroelectrics


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Date

2023-12

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

Material surfaces encompass structural and chemical discontinuities that often lead to the loss of the property of interest in so-called dead layers. It is particularly problematic in nanoscale oxide electronics, where the integration of strongly correlated materials into devices is obstructed by the thickness threshold required for the emergence of their functionality. Here we report the stabilization of ultrathin out-of-plane ferroelectricity in oxide heterostructures through the design of an artificial flux-closure architecture. Inserting an in-plane-polarized ferroelectric epitaxial buffer provides the continuity of polarization at the interface; despite its insulating nature, we observe the emergence of polarization in our out-of-plane-polarized model of ferroelectric BaTiO₃ from the very first unit cell. In BiFeO₃, the flux-closure approach stabilizes a 251° domain wall. Its unusual chirality is probably associated with the ferroelectric analogue to the Dzyaloshinskii–Moriya interaction. We, thus, see that in an adaptively engineered geometry, the depolarizing-field-screening properties of an insulator can even surpass those of a metal and be a source of functionality. This could be a useful insight on the road towards the next generation of oxide electronics.

Publication status

published

Editor

Book title

Volume

22 (12)

Pages / Article No.

1492 - 1498

Publisher

Nature

Event

Edition / version

Methods

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Geographic location

Date collected

Date created

Subject

Ferroelectrics and multiferroics; Surfaces, interfaces and thin films; Topological defects

Organisational unit

03918 - Fiebig, Manfred / Fiebig, Manfred check_circle

Notes

Funding

188414 - Multifunctional oxide electronics using natural ferroelectric superlattices (SNF)
694955 - In-situ second harmonic generation for emergent electronics in transition-metal oxides (EC)
178825 - Dynamical processes in systems with strong electronic correlations (SNF)

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