小さなScは鎖を揺さぶる:ScV6Sn6における電荷密度波に対するLuとYドーピングの影響
William R Meier1, Richa Pokharel Madhogaria1, Shirin Mozaffari1
1Materials Science & Engineering Department, University of Tennessee Knoxville, Knoxville, Tennessee 37996, United States.
Journal of the American Chemical Society
|September 14, 2023
まとめ
稀土の大きさは,カゴム金属の電荷密度波 (CDW) の鍵です. より小さなScをより大きな希土で置き換えると,CDWを抑制し,この現象はラッティングチェーンモデルによって説明されます.
科学分野:
- 凝縮物質物理学
- 材料科学
- 固体化学
背景:
- カゴメの金属は,独特の格子構造により,多様な電子と磁気相を示す.
- いくつかのバナジウムカゴム網材料は低温で電荷密度波 (CDW) を形成する.
- RV6Sn6シリーズは,HfFe6Ge6タイプの構造で,Rがスカンジウム (Sc) である場合にのみCDWを独占的にホストします.
研究 の 目的:
- RV6Sn6化合物のCDW形成に対する希土元素の大きさの影響を調査する.
- ScV6Sn6における選択的なCDW形成の背後にあるメカニズムを解明する.
主な方法:
- (Sc,Lu) V6Sn6と (Sc,Y) V6の単結晶の合成
- CDW抑制を評価するための磁気化測定.
- 構造変化を分析するために単一結晶X線 difraktion.
主要な成果:
- RV6Sn6におけるCDW形成は,ScをLuやYのようなより大きな希土元素に置き換えることで抑制される.
- 圧縮可能なSn-Sn結合は,大きなレアアースを重要な格子膨張なしに容納します.
- 物理的な圧力とより大きな希土原子の両方がCDWの形成を妨げていることを説明します.
結論:
- Scの小さなイオン半径は,R-Sn-Sn鎖内に必要な空間を提供することによって,ScV6Sn6のCDW形成に不可欠である.
- 圧力と置換の両方によってCDWの抑制をうまく説明しています.
- この研究は,カゴム金属内のCDW現象における稀土の大きさの特定の役割を明確にします.
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