TY - JOUR
T1 - Evidence for a cos (4φ) modulation of the superconducting energy gap of optimally doped FeTe0.6Se0.4 single crystals using laser angle-resolved photoemission spectroscopy
AU - Okazaki, K.
AU - Ito, Y.
AU - Ota, Y.
AU - Kotani, Y.
AU - Shimojima, T.
AU - Kiss, T.
AU - Watanabe, S.
AU - Chen, C. T.
AU - Niitaka, S.
AU - Hanaguri, T.
AU - Takagi, H.
AU - Chainani, A.
AU - Shin, S.
PY - 2012/12/6
Y1 - 2012/12/6
N2 - We study the superconducting-gap anisotropy of the Γ-centered hole Fermi surface in optimally doped FeTe0.6Se0.4 (T c=14.5 K), using laser-excited angle-resolved photoemission spectroscopy. We observe sharp superconducting (SC) coherence peaks at T=2.5 K. In contrast to earlier angle-resolved photoemission spectroscopy studies but consistent with thermodynamic results, the momentum dependence shows a cos (4φ) modulation of the SC-gap anisotropy. The observed SC-gap anisotropy strongly indicates that the pairing interaction is not a conventional phonon-mediated isotropic one. Instead, the results suggest the importance of second-nearest-neighbor electronic interactions between the iron sites in the framework of s±-wave superconductivity.
AB - We study the superconducting-gap anisotropy of the Γ-centered hole Fermi surface in optimally doped FeTe0.6Se0.4 (T c=14.5 K), using laser-excited angle-resolved photoemission spectroscopy. We observe sharp superconducting (SC) coherence peaks at T=2.5 K. In contrast to earlier angle-resolved photoemission spectroscopy studies but consistent with thermodynamic results, the momentum dependence shows a cos (4φ) modulation of the SC-gap anisotropy. The observed SC-gap anisotropy strongly indicates that the pairing interaction is not a conventional phonon-mediated isotropic one. Instead, the results suggest the importance of second-nearest-neighbor electronic interactions between the iron sites in the framework of s±-wave superconductivity.
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U2 - 10.1103/PhysRevLett.109.237011
DO - 10.1103/PhysRevLett.109.237011
M3 - Article
AN - SCOPUS:84870945173
VL - 109
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 23
M1 - 237011
ER -