鉛カルコゲニドのエントロピー的に安定した局所二極形成
Emil S Božin1, Christos D Malliakas, Petros Souvatzis
1Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
Science (New York, N.Y.)
|December 18, 2010
まとめ
ローカルな構造的二極は,鉛カルコゲニドの加熱時に発生し,従来の相変化に逆らいます. コンフィギュレーションエントロピーによって導かれるこの発見は,それらの異常な電子的および熱電気的性質を説明します.
科学分野:
- 材料科学 材料科学とは
- 固体物理 固体物理学
- クリスタルグラフィーです.
背景:
- 従来の構造的相変遷は,冷却時に発生する歪みを伴う.
- バイナリ鉛カルコゲニドは,すべての温度において歪みのない岩塩構造を有すると推定された.
- 局所構造を理解することは,異常な性質を持つ材料にとって極めて重要です.
研究 の 目的:
- バイナリ鉛カルコゲニドの温暖化時に発生する局所構造的二極の新しい観察を報告するために.
- この異常なフェーズ行動の背後にある熱力学的原動力を調査するために.
- 局所構造とこれらの材料の異常な電子/熱電気特性との関連を解明する.
主な方法:
- 局所構造の実験的な探査.
- 理論モデリングとシミュレーション.
- 構成エントロピーを含む熱力学モデルの分析.
主要な成果:
- 温暖化時の歪みのない基底状態から現われる局所構造二極の観測.
- この現象の実証は,二重鉛カルコゲニドで示した.
- コンフィギュレーションエントロピーが高温で二極を安定させる熱力学モデルの検証.
結論:
- 温暖化における局所構造的二極の出現は,従来の相変遷とは異なる新しい現象である.
- 構成エントロピーは,これらの二極を高温で安定させる上で重要な役割を果たします.
- これらの発見は,鉛カルコゲニドの異常な電子および熱電気的振る舞いを洞察し,この現象が広範囲に及ぶ可能性があることを示唆しています.
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