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arXiv 1412.0945cond-mat.supr-con
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KFe2As2中范霍夫奇异性的观测及其对强耦合诱导库珀对的意义

Observation of a van Hove singularity and implication for strong coupling induced Cooper pairing in KFe2As2

Delong Fang, Xun Shi, Zengyi Du, Pierre Richard, Huan Yang, X. X. Wu, Peng Zhang, Tian Qian, Xiaxin Ding, Zhenyu Wang, T. K. Kim, M. Hoesch, Aifeng Wang, Xianhu… 展开作者

Delong Fang, Xun Shi, Zengyi Du, Pierre Richard, Huan Yang, X. X. Wu, Peng Zhang, Tian Qian, Xiaxin Ding, Zhenyu Wang, T. K. Kim, M. Hoesch, Aifeng Wang, Xianhui Chen, Jiangping Hu, Hong Ding, Hai-Hu Wen

摘要:

对KFe_2As_2单晶样品进行了扫描隧道谱和角分辨光电子能谱研究。在超导KFe_2As_2的费米能级E_F以下几meV处,直接观测到了位于第一布里渊区主轴中心的范霍夫奇点(vHs)。在超导态下,E_F处的态密度主要是由鞍点对E_F的邻近效应所贡献的,并且大部分是无能隙的。我们观察到的节点行为的动量区域接近vHs点,同时提供一致的解释,许多奇异的行为,以前在这种材料中观察到的,表明库珀配对诱导的强耦合机制。

英文摘要:

Scanning tunneling spectroscopy (STS) and angle-resolved photoemission spectroscopy (ARPES) have been investigated on single crystal samples of KFe2As2. A van Hove singularity (vHs) has been directly observed just a few meV below the Fermi level E_F of superconducting KFe2As2, which locates in the middle of the principle axes of the first Brillouin zone. The majority of the density-of-states at E_F, mainly contributed by the proximity effect of the saddle point to E_F, is non-gapped in the superconducting state. Our observation of nodal behavior of the momentum area close to the vHs points, while providing consistent explanations to many exotic behaviours previously observed in this material, suggests Cooper pairing induced by a strong coupling mechanism.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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