Unconventional superconducting gap in NaFe0.95Co 0.05As observed by angle-resolved photoemission spectroscopy

Z. H. Liu, P. Richard, K. Nakayama, G. F. Chen, S. Dong, J. B. He, D. M. Wang, T. L. Xia, K. Umezawa, T. Kawahara, S. Souma, T. Sato, T. Takahashi, T. Qian, Yaobo Huang, Nan Xu, Yingbo Shi, H. Ding, S. C. Wang

研究成果: Article査読

72 被引用数 (Scopus)

抄録

We have performed high-resolution angle-resolved photoemission measurements on superconducting electron-doped NaFe0.95Co0.05As (Tc∼18K). We observed a holelike Fermi surface around the zone center and two electronlike Fermi surfaces around the M point, which can be connected by the Q=(π,π) wave vector, suggesting that scattering over the near-nested Fermi surfaces is important in this 111 pnictide. Nearly isotropic superconducting gaps with sharp coherent peaks are observed below Tc on all three Fermi surfaces. Upon increasing temperature through Tc, the gap size shows little change while the coherence vanishes. Large ratios of 2Δ/kBTc∼8 are observed for all the bands, indicating a strong coupling in this system. These results are not expected from a classical phonon-mediated pairing mechanism.

本文言語English
論文番号064519
ジャーナルPhysical Review B - Condensed Matter and Materials Physics
84
6
DOI
出版ステータスPublished - 2011 8 23

ASJC Scopus subject areas

  • 電子材料、光学材料、および磁性材料
  • 凝縮系物理学

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