在SmFeAsO{1 - x) F{x) 和Ba{1 - x) K{x) Fe{2}As{2}中有一个大的铁同位素效应
1Hefei National Laboratory for Physical Sciences at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Nature
|May 9, 2009
概括
在oxypnictides中的高温超导性不仅仅是由于电子-声子相互作用. 铁同位素的替换影响了超导和自旋密度波的过渡,这表明了复杂的相互作用.
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
- 超导性研究 超导性研究
背景情况:
- 在超过麦克米伦极限的oxypnictides超导性的发现.
- 关于该机制的理论辩论:电子 - 声子相互作用与磁波动.
- 在pnictides中观察到超导和磁性对晶格的敏感性.
研究的目的:
- 调查电子 - 声子相互作用在oxypnictide超导性中的作用.
- 确定氧气和铁同位素替代对临界温度的影响.
- 探索超导和自旋密度波过渡之间的关系.
主要方法:
- 在SmFeAsO{1-x) F{x) 和Ba{1-x) K{x) Fe{2) As{2) 系统中,氧和铁同位素的替代.
- 测量超导的临界过渡温度 (T ((C)) .
- 旋转密度波 (SDW) 过渡温度 (T(SDW)) 的测量.
- 对T (C) 和T (SDW) 的同位素影响的分析.
主要成果:
- 氧同位素对T (C) 和T (SDW) 的作用最小.
- 铁同位素对T (C) 的显著影响,其指数 (alpha (C)) 约为0.35.
- 铁同位素替代影响T ((SDW) 与T ((C)) 类似.
- 观察到的同位素效应表明电子 - 声子相互作用的作用,但不仅如此.
结论:
- 电子 - 声子相互作用有助于这些材料的超导性.
- 一个简单的电子音声合模型不足以解释这些发现.
- 强大的磁声声合可能参与了超导机制.
- 磁力和格子振动之间的相互作用对于氧尼克特的高T (C) 超导性至关重要.
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