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Fabrication and Optimization of Type II Silicon Clathrate Films
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シリコン一酸化物 1 atm と高圧:結晶か無形か?
Khalid AlKaabi1, Dasari L V K Prasad, Peter Kroll
1Department of Chemistry and Chemical Biology, Cornell University , Ithaca, New York 14853, United States.
Journal of the American Chemical Society
|February 6, 2014
まとめ
この研究では,圧迫下にあるシリコン一酸化物 (SiO) の構造を理論的に調査しています. 安定した基底状態と高圧相を明らかにし,SiOは高圧では金属であるが,不釣り合いである.
科学分野:
- マテリアルサイエンス 材料科学
- コンピューティング・ケミストリー
- 固体物理 固体物理学
背景:
- シリコン一酸化物 (SiO) は,環境条件では結晶相がないため,異常です.
- グループ14のモノ酸化物は,異なる安定性と不釣り合いの行動を示す.
研究 の 目的:
- 理論的に SiO の秩序付けられた基底状態と無形構造を 1 atm で探求する.
- 高圧 (最大200GPa) 下で結晶SiO相を調査する.
- 結晶SiOの形成熱と不均衡を計算する.
主な方法:
- 1 atmで基底状態と無形構造の理論的計算.
- 200GPaまでの高圧フェーズ探査.
- 形成熱と不均衡に対する熱力学的計算.
主要な成果:
- 1 atmでのSiOのためのいくつかの競争的なグラウンドステート構造が特定され,Si-SiボンドとSi-O-Siブリッジが特徴でした.
- アモルフなSiOモデルは,SiとSiO2領域に分離していないことを示した.
- 新しい結晶構造が高圧で進化し,Siの三角形の網/ストライプやスティショライトのような領域が含まれています.
- 結晶SiOは,グループ14のモノ酸化物の中で最も負の形成熱を持っています.
- SiOとSiとSiO2の不釣り合いはエクソテルミックであり,グループ14のモノ酸化物の傾向と一致する.
- 高圧SiO相は金属であることが判明しました.
結論:
- SiOは,環境および高圧で複雑な構造を示し,その異常な状態に挑戦します.
- 形成熱の負の値にもかかわらず,SiOはSiとSiO2.2への不均衡化に関して不安定です.
- SiO相における圧力誘発の金属性は,重要な発見である.
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