Abstract

The interplay of orbital and spin degrees of freedom is the fundamental characteristic in numerous condensed matter phenomena, including high-temperature superconductivity, quantum spin liquids, and topological semimetals. In iron-based superconductors (FeSCs), this causes superconductivity to emerge in the vicinity of two other instabilities: nematic and magnetic. Unveiling the mutual relationship among nematic order, spin fluctuations, and superconductivity has been a major challenge for research in FeSCs, but it is still controversial. Here, by carrying out 77Se nuclear magnetic resonance (NMR) measurements on FeSe single crystals, doped by cobalt and sulfur that serve as control parameters, we demonstrate that the superconducting transition temperature Tc increases in proportion to the strength of spin fluctuations, while it is independent of the nematic transition temperature Tnem. Our observation therefore directly implies that superconductivity in FeSe is essentially driven by spin fluctuations in the intermediate coupling regime, while nematic fluctuations have a marginal impact on Tc.

Details

Title
Separate tuning of nematicity and spin fluctuations to unravel the origin of superconductivity in FeSe
Author
Seung-Ho, Baek 1   VIAFID ORCID Logo  ; Ok Jong Mok 2 ; Kim, Jun Sung 2 ; Saicharan, Aswartham 3   VIAFID ORCID Logo  ; Morozov, Igor 4 ; Chareev Dmitriy 5 ; Urata Takahiro 6 ; Tanigaki Katsumi 7 ; Tanabe Yoichi 8 ; Büchner Bernd 9 ; Efremov, Dmitri V 3 

1  Changwon National University, Department of Physics, Changwon, Korea (GRID:grid.411214.3) (ISNI:0000 0001 0442 1951) 
2  Pohang University of Science and Technology, Department of Physics, Pohang, Korea (GRID:grid.49100.3c) (ISNI:0000 0001 0742 4007); Institute of Basic Science, Center for Artificial Low Dimensional Electronic Systems, Pohang, Korea (GRID:grid.410720.0) (ISNI:0000 0004 1784 4496) 
3  IFW Dresden, Dresden, Germany (GRID:grid.14841.38) (ISNI:0000 0000 9972 3583) 
4  IFW Dresden, Dresden, Germany (GRID:grid.14841.38) (ISNI:0000 0000 9972 3583); Moscow State University, Moscow, Russia (GRID:grid.14476.30) (ISNI:0000 0001 2342 9668) 
5  Russian Academy of Sciences, Institute of Experimental Mineralogy, Moscow, Russia (GRID:grid.4886.2) (ISNI:0000 0001 2192 9124); Ural Federal University, Ekaterinburg, Russia (GRID:grid.412761.7) (ISNI:0000 0004 0645 736X); Kazan Federal University, Kazan, Russia (GRID:grid.77268.3c) (ISNI:0000 0004 0543 9688) 
6  Tohoku University, Department of Physics, Graduate School of Science, Sendai, Japan (GRID:grid.69566.3a) (ISNI:0000 0001 2248 6943); Nagoya University, Department of Materials Physics, Chikusa-ku, Japan (GRID:grid.27476.30) (ISNI:0000 0001 0943 978X) 
7  Tohoku University, Department of Physics, Graduate School of Science, Sendai, Japan (GRID:grid.69566.3a) (ISNI:0000 0001 2248 6943) 
8  Tohoku University, Department of Physics, Graduate School of Science, Sendai, Japan (GRID:grid.69566.3a) (ISNI:0000 0001 2248 6943); Okayama University of Science, Department of Science, Okayama, Japan (GRID:grid.444568.f) (ISNI:0000 0001 0672 2184) 
9  IFW Dresden, Dresden, Germany (GRID:grid.14841.38) (ISNI:0000 0000 9972 3583); Technische Universität Dresden, Department of Physics, Dresden, Germany (GRID:grid.4488.0) (ISNI:0000 0001 2111 7257) 
Publication year
2020
Publication date
2020
Publisher
Nature Publishing Group
e-ISSN
23974648
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1038/s41535-020-0211-y
ProQuest document ID
2488776074
Copyright
© The Author(s) 2020. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.