Unconventional anisotropic s-Wave superconducting gaps of the LiFeAs Iron-Pnictide superconductor

K. Umezawa, Y. Li, H. Miao, K. Nakayama, Z. H. Liu, P. Richard, T. Sato, J. B. He, D. M. Wang, G. F. Chen, H. Ding, T. Takahashi, S. C. Wang

Research output: Contribution to journalArticlepeer-review

149 Citations (Scopus)

Abstract

We have performed high-resolution angle-resolved photoemission spectroscopy on Fe-based superconductor LiFeAs (T c=18K). We reveal multiple nodeless superconducting (SC) gaps with 2Δ/k BT c ratios varying from 2.8 to 6.4, depending on the Fermi surface (FS). We also succeeded in directly observing a gap anisotropy along the FS with magnitude up to ∼30%. The anisotropy is fourfold symmetric with an antiphase between the hole and electron FSs, suggesting complex anisotropic interactions for the SC pairing. The observed momentum dependence of the SC gap offers an excellent opportunity to investigate the underlying pairing mechanism.

Original languageEnglish
Article number037002
JournalPhysical review letters
Volume108
Issue number3
DOIs
Publication statusPublished - 2012 Jan 20

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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