Anisotropy of the superconducting gap in the iron-based superconductor BaFe2(As(1-x)P(x))2

T Yoshida; S Ideta; T Shimojima; W Malaeb; K Shinada; H Suzuki; I Nishi; A Fujimori; K Ishizaka; S Shin; Y Nakashima; H Anzai; M Arita; A Ino; H Namatame; M Taniguchi; H Kumigashira; K Ono; S Kasahara; T Shibauchi; T Terashima; Y Matsuda; M Nakajima; S Uchida; Y Tomioka; T Ito; K Kihou; C H Lee; A Iyo; H Eisaki; H Ikeda; R Arita; T Saito; S Onari; H Kontani

doi:10.1038/srep07292

Anisotropy of the superconducting gap in the iron-based superconductor BaFe2(As(1-x)P(x))2

Sci Rep. 2014 Dec 3:4:7292. doi: 10.1038/srep07292.

Authors

T Yoshida¹, S Ideta², T Shimojima³, W Malaeb⁴, K Shinada³, H Suzuki², I Nishi², A Fujimori¹, K Ishizaka³, S Shin⁴, Y Nakashima⁵, H Anzai⁶, M Arita⁶, A Ino⁵, H Namatame⁶, M Taniguchi⁷, H Kumigashira⁸, K Ono⁸, S Kasahara⁹, T Shibauchi¹⁰, T Terashima¹¹, Y Matsuda¹⁰, M Nakajima², S Uchida¹, Y Tomioka¹², T Ito¹², K Kihou¹², C H Lee¹², A Iyo¹², H Eisaki¹², H Ikeda¹³, R Arita¹⁴, T Saito¹⁵, S Onari¹⁶, H Kontani¹⁵

Affiliations

¹ 1] Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan [2] JST, Transformative Research-Project on Iron Pnictides (TRIP), Chiyoda, Tokyo 102-0075, Japan.
² Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
³ Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
⁴ Institute of Solid State Physics, University of Tokyo, Kashiwa 277-8581, Japan.
⁵ Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan.
⁶ Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan.
⁷ 1] Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan [2] Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima 739-0046, Japan.
⁸ KEK, Photon Factory, Tsukuba, Ibaraki 305-0801, Japan.
⁹ 1] Research Center for Low Temperature and Materials Sciences, Kyoto University, Kyoto 606-8502, Japan [2] Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
¹⁰ Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
¹¹ Research Center for Low Temperature and Materials Sciences, Kyoto University, Kyoto 606-8502, Japan.
¹² 1] JST, Transformative Research-Project on Iron Pnictides (TRIP), Chiyoda, Tokyo 102-0075, Japan [2] National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568, Japan.
¹³ 1] JST, Transformative Research-Project on Iron Pnictides (TRIP), Chiyoda, Tokyo 102-0075, Japan [2] Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
¹⁴ 1] JST, Transformative Research-Project on Iron Pnictides (TRIP), Chiyoda, Tokyo 102-0075, Japan [2] Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.
¹⁵ 1] JST, Transformative Research-Project on Iron Pnictides (TRIP), Chiyoda, Tokyo 102-0075, Japan [2] Department of Physics, Nagoya University, Furo-cho, Nagoya 464-8602, Japan.
¹⁶ 1] JST, Transformative Research-Project on Iron Pnictides (TRIP), Chiyoda, Tokyo 102-0075, Japan [2] Department of Applied Physics, Nagoya University, Furo-cho, Nagoya 464-8602, Japan.

Abstract

We report peculiar momentum-dependent anisotropy in the superconducting gap observed by angle-resolved photoemission spectroscopy in BaFe2(As(1-x)P(x))2 (x = 0.30, Tc = 30 K). Strongly anisotropic gap has been found only in the electron Fermi surface while the gap on the entire hole Fermi surfaces are nearly isotropic. These results are inconsistent with horizontal nodes but are consistent with modified s ± gap with nodal loops. We have shown that the complicated gap modulation can be theoretically reproduced by considering both spin and orbital fluctuations.

Publication types

Research Support, Non-U.S. Gov't