空白と化学的順序による逆対称性のない極性酸化物

Joshua Young^1,2, Eun Ju Moon¹, Debangshu Mukherjee³

¹Department of Materials Science and Engineering, Drexel University , Philadelphia, Pennsylvania 19104, United States.

Journal of the American Chemical Society

|February 7, 2017

まとめ

研究者たちは薄膜に原子を精密に並べることで新種の極性物質を作り出しましたこの結晶化学の設計アプローチは,アニオンとカチオンを順番に並べて,オリジナルの化合物にはないユニークな性質を持つ新しい構造を生成します.

科学分野:

材料科学
固体化学
クリスタルグラフィー

背景:

材料の発見にはしばしば化合物を混合し,性質は通常成分平均に従います.
移行金属酸化物 (TMO) では,ナノ構造化により新しいポリモルフと特性が生成される.
デジタルナノ構造は構成要素の性質を超えて材料を設計するための経路を提供します

研究の目的:

逆対称性のないデジタルTMOを作成するための結晶化学設計戦略を開発する.
周期的なアニオン空位順とカチオン順を利用して極性構造を達成する.
センター対称ブラウンミレライトTMOを用いてこのアプローチを実証する.

主な方法:

デジタルTMOのための結晶化学設計アプローチの策定.
エピタキシアル (SrFeO2.5) / ((CaFeO2.5) 1) 薄膜超網の合成
シンクロトロンベースの屈折と偏差修正電子顕微鏡を用いた特徴付け.
シンメトリー分析と密度関数理論の計算

主要な成果:

サブナノメートルのアニオン空白とカチオン順序でエピタキシアルスーパーラットスを成功裏に実現した.
Sr/Caの化学順序とアニオン空間の順序の両方の存在を確認しました.
Aサイトカトンの順序が逆対称性を破り,極性構造を生成することを示した.
ナノスケールの順序付けは,親化合物とは異なる非中心的な構造を生成することを示した.

結論:

アニオンとカチオンの順序のナノスケール制御は,非中心的なTMOの設計を可能にします.
この戦略では大量成分に含まれない性質の材料を生成します
新しい機能材料の構造ベースの設計のための新しい道を開きます.

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