La2 - xSrxCuO4における超伝導体 - 絶縁体の移行は,量子抵抗のペアで起こる
A T Bollinger1, G Dubuis, J Yoon
1Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
Nature
|April 29, 2011
まとめ
研究者らは超伝導体-絶縁体の移行を超薄なLa{2-x) Sr{x) CuO{4) フィルムで調査した. 彼らはクーパー対の量子抵抗に匹敵する臨界抵抗を観察し,量子相移行を示した.
科学分野:
- 凝縮物質物理学 凝縮物質物理学
- 材料科学 材料科学とは
背景:
- 銅酸化物の高温超伝導性は,臨界濃度を超えたドーピングに関連しています.
- 超伝導体-断熱器の移行を理解することは,この分野を前進させるために不可欠です.
- SrTiOに関する以前の研究では,電場が超伝導性に与える影響が示されていた.
研究 の 目的:
- 超伝導体-断熱器の移行を超薄なLa(2-x) Sr(x) CuO(4) フィルムで調査する.
- 銅酸化物におけるキャリア密度に対する大きな電場効果を達成するために.
- この移行における量子変動の役割を調査する.
主な方法:
- エピタキシアル,単細胞厚さのLa{2-x}Sr{x}CuO{4) フィルムの合成.
- イオン性液体を使用した電気双層トランジスタの製造.
- 高電場下での温度とキャリア密度に対する抵抗の測定.
主要な成果:
- 大きな電場を使用して,最大30Kの臨界温度シフトを達成しました.
- 2D超伝導体-断熱器移行理論と一致する,単一の関数に崩壊する抵抗データを観察した.
- R(Q) = h/(2e) (6.45 kΩ) の臨界抵抗を特定しました.
結論:
- この発見は,量子相変動によって引き起こされる量子相変遷を示唆している.
- 結果は,Cooper Pairのデロカライゼーションを重要なメカニズムとして示しています.
- この研究は,銅酸化物における超伝導性を調節するための新しい方法を提供します.
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