在高Tc超导体Bi2Sr2CaCu2O8+delta中,在原子尺度上可视化对形成
Kenjiro K Gomes1, Abhay N Pasupathy, Aakash Pushp
1Department of Physics, Joseph Henry Laboratories, Princeton University, Princeton, New Jersey 08544, USA.
Nature
|June 1, 2007
概括
在高温超导体中,电子配对间隙在临界温度 (Tc) 以上的纳米级区域中形成. 这些局部配对现象为理解波动超导提供了微观基础.
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:
- 传统的超导体在超导过渡温度 (Tc) 上呈现电子配对,形成能量间隙 (Delta).
- 高Tc超导体在Tc以上的电子状态密度 (DOS) 中显示了部分差距,这引发了关于其与配对相关性的疑问.
研究的目的:
- 研究高Tc超导体中的配对间隙的空间和温度依赖的形成.
- 为了确定间隙形成和不连贯对形成的温度之间的关系.
主要方法:
- 使用扫描道显微镜 (STM) 进行空间分辨率的测量.
- 对具有不同临界温度 (Tc) 和孔度 (0.12至0.22) 的Bi2Sr2CaCu2O8+delta样本进行分析.
主要成果:
- 配对间隙在Tc以上的纳米级区域中核化,用于0.16至0.22.2的兴奋剂水平.
- 这些纳米配对区域随着温度的下降而增多,导致差距大小的分布.
- 每个配对间隙在局部形成的特征温度Tp,以下2Delta/k(B) Tp = 7.9 ± 0.5.5.
- 在低兴奋剂 (<0.14) 时,明显的DOS变化表明与电子配对竞争的现象.
结论:
- 这项研究揭示了第一个直接的,空间分辨率的证据,表明在Tc以上的高Tc超导体中存在纳米尺寸的配对区域.
- 这些发现为以前在类似材料中观察到的高于Tc的波动超导反应提供了微观解释.
- 结果突出了高Tc超导体中的配对和其他电子现象的复杂相互作用.
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