Rational Assembly of Two-Dimensional Perovskite Nanosheets as Building Blocks for New Ferroelectrics

Muhammad Shuaib Khan, Minoru Osada, Lei Dong, Yoon Hyun Kim, Yasuo Ebina, Takayoshi Sasaki

Research output: Contribution to journalArticlepeer-review

Abstract

Artificial materials in the form of superlattices have been studied actively in quest of new engineering methods or design rules for the development of desired functionalities, in particular high-k ferroelectricity, ferromagnetism, and high mobility electron gas. This work presents a controlled assembly strategy for fabricating atomically precise interfaces of two-dimensional (2D) homologous perovskite nanosheets (Ca2Nam-3NbmO3m+1- m = 3-6) to construct artificial superlattices. The distinctive thickness of each 2D homologous perovskite nanosheets attributed to the presence of different number of NbO6 octahedra provides an exquisite control to engineer interfacial properties for tailored design of superior high-k properties and emergence of ferroelectricity. The higher dielectric constant (ϵr = 427) and development of ferroelectricity for (Ca2Nb3O10-/Ca2Na2Nb5O16-)6 superlattice indicate that superlattice films with both odd number of NbO6 octahedra possess extended polarization due to the potential effect of heterointerface and ferroelectric instabilities. Furthermore, the increased discontinuities/offsets in Ca2Nb3O10- and Ca2Na3Nb6O19- nanosheets band alignment results in superior insulating properties (μ1 × 10-11 A cm-2 at 1 V) for (Ca2Nb3O10-/Ca2Na3Nb6O19-)6 superlattice. These findings exhibit new research opportunities for the development of novel artificial high-k dielectric/ferroelectric via precise control of interfaces at the atomic level and can be extended to the large family of 2D perovskite compounds.

Original languageEnglish
Pages (from-to)1783-1790
Number of pages8
JournalACS Applied Materials and Interfaces
Volume13
Issue number1
DOIs
Publication statusPublished - 2021 Jan 13
Externally publishedYes

Keywords

  • 2D perovskite oxides
  • artificial superlattices
  • ferroelectrics
  • interface engineering
  • layer-by-layer assembly

ASJC Scopus subject areas

  • Materials Science(all)

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