構造的相変遷と超伝導性は,環境および高圧下においてFe(1+デルタ) Se0.57Te0.43で表される
Nathalie C Gresty1, Yasuhiro Takabayashi, Alexey Y Ganin
1Department of Chemistry, Durham University, Durham DH1 3LE, UK.
Journal of the American Chemical Society
|October 30, 2009
まとめ
圧力は鉄カルコゲニドの超伝導性を著しく高め,臨界温度 (T (c)) は23.3Kでピークに達する. 3GPaでモノクリニック対称性への構造的シフトは最大T (c) と相関し,結晶と電子特性の間の関連性を明らかにする.
科学分野:
- 凝縮物質物理学 凝縮物質物理学
- マテリアルサイエンス 材料科学
- 固体化学 固体化学
背景:
- Feベースの超伝導体は,ユニークな性質を持つ,最近発見された材料のクラスです.
- Fe ((1.03) Se ((0.57) Te ((0.43)) のような三次鉄カルコゲニドは,環境圧下では超伝導性を示す.
- 構造と超伝導性の相互作用を理解することは,新しい材料の設計に不可欠です.
研究 の 目的:
- 圧力下にあるFe (−1.03) Se (−0.57) Te (−0.43) の構造特性と電子特性との関係を調査する.
- 施した圧力が,超伝導体の臨界温度 (T (c)) にどのように影響するかを決定する.
- 圧力によって誘発される構造的相変遷を調査する.
主な方法:
- 構造変化を分析するために,高解像度のシンクロトロンX線 difraktion が使用されました.
- 超伝導的臨界温度 (T(c)) は,加圧の関数として測定された.
- 結晶構造と対称性は,様々な圧力点で特徴づけられました.
主要な成果:
- 超伝導的臨界温度 (T(c)) は圧力とともに上昇し,約3GPaで最大23.3Kに達した.
- オーソロンビック対称性からモノクリニック対称性への構造的変換は,約3GPaで発生しました.
- より高い圧力 (12 GPa) で,材料は金属化し,超伝導性を失いました.
結論:
- 結晶構造と鉄カルコゲニド超伝導体の電子特性との間には密接な関係がある.
- 圧力によって引き起こされる構造的対称性の変化は,超伝導体の動作に直接影響します.
- この発見は,これらの材料における超伝導性のメカニズムについての洞察を提供します.
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