在超导体 SmFeAsO0.85F0.1515 中有一个类似于BCS的空隙.
T Y Chen1, Z Tesanovic, R H Liu
1Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Nature
|June 6, 2008
概括
研究人员使用安德列夫光谱学观察到SmFeAsO{0.85) F{0.15) 中的单个超导差距. 这一发现与Bardeen-Cooper-Schrieffer (BCS) 理论一致,不同于高温氧化铜超导体.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 材料科学 材料科学 材料科学
- 超导电性 超导电性 超导电性
背景情况:
- 铜氧化物的高过渡温度 (高Tc) 超导性依赖于CuO2) 平面.
- 一个新型的氧尼克类超导体,LaFeAsO{1-x) F{x),缺乏CuO{2}平面,这表明了替代的配对机制.
- 超导间隙的特性对于理解配对机制至关重要.
研究的目的:
- 为了研究氧尼化超导体SmFeAsO ((0.85) F ((0.15)) 中的超导间隙.
- 将观察到的间隙行为与巴丁-库珀-施里弗 (BCS) 理论和氧化铜超导体进行比较.
- 为了确定差距顺序参数的性质 (节点/无节点,同otropic/异otropic).
主要方法:
- 安德烈耶夫光谱法被用来测量超导间隙.
- 研究了差距的温度依赖性.
- 计算了2Delta/kBTc的比率,并与理论预测进行了比较.
主要成果:
- 在SmFeAsO{0.85) F{0.15) 中观察到一个单一的超导间隙,T{c) = 42 K.
- 差距值为2Delta = 13.34 +/- 0.3 meV,产生2Delta/k(B) T(c) = 3.68,接近BCS预测 (3.53) 的值.
- 间隙表现出BCS一致的温度依赖性,并且没有节点,几乎是同otropic,不像铜氧化物中的伪间隙.
结论:
- 结果表明SmFeAsO中的配对机制{0.85) F{0.15) 与氧化铜超导体中的配对机制不同.
- 观察到的无节点和几乎同位素差距与基于反铁磁波动或与高T (c) 相相关的强相关性模型不兼容.
- 这项研究提供了关于铁基氧基基基基基基基基基基基基基基的基本性质的关键见解.
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