Abstract

Nematic order often breaks the tetragonal symmetry of iron-based superconductors. It arises from regular structural transition or electronic instability in the normal phase. Here, we report the observation of a nematic superconducting state, by measuring the angular dependence of the in-plane and out-of-plane magnetoresistivity of Ba0.5K0.5Fe2As2 single crystals. We find large twofold oscillations in the vicinity of the superconducting transition, when the direction of applied magnetic field is rotated within the basal plane. To avoid the influences from sample geometry or current flow direction, the sample was designed as Corbino-shape for in-plane and mesa-shape for out-of-plane measurements. Theoretical analysis shows that the nematic superconductivity arises from the weak mixture of the quasi-degenerate s-wave and d-wave components of the superconducting condensate, most probably induced by a weak anisotropy of stresses inherent to single crystals.

Details

Title
Nematic superconducting state in iron pnictide superconductors
Author
Li, Jun 1 ; Pereira, Paulo J 2 ; Yuan, Jie 3 ; Yang-Yang, Lv 4 ; Mei-Ping, Jiang 4 ; Lu, Dachuan 4 ; Zi-Quan, Lin 5 ; Yong-Jie, Liu 5 ; Jun-Feng, Wang 5 ; Li, Liang 5 ; Ke, Xiaoxing 6 ; Gustaaf Van Tendeloo 6 ; Meng-Yue, Li 7 ; Hai-Luke, Feng 8 ; Hatano, Takeshi 8 ; Hua-Bing, Wang 7 ; Pei-Heng, Wu 9 ; Yamaura, Kazunari 10   VIAFID ORCID Logo  ; Takayama-Muromachi, Eiji 10 ; Vanacken, Johan 11 ; Chibotaru, Liviu F 12 ; Moshchalkov, Victor V 11 

1  Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China; National Institute for Materials Science, Tsukuba, Japan; INPAC-Institute for Nanoscale Physics and Chemistry, KU Leuven, Leuven, Belgium 
2  INPAC-Institute for Nanoscale Physics and Chemistry, KU Leuven, Leuven, Belgium; Theory of Nanomaterials Group, KU Leuven, Leuven, Belgium 
3  Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China; National Institute for Materials Science, Tsukuba, Japan; National Laboratory for Superconductivity, Institute of Physics, and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing, China 
4  Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China 
5  Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology, Wuhan, China 
6  Electron Microscopy for Materials Research (EMAT), University of Antwerp, Antwerp, Belgium 
7  Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China; National Institute for Materials Science, Tsukuba, Japan 
8  National Institute for Materials Science, Tsukuba, Japan 
9  Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China; Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui, China 
10  National Institute for Materials Science, Tsukuba, Japan; Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo, Japan 
11  INPAC-Institute for Nanoscale Physics and Chemistry, KU Leuven, Leuven, Belgium 
12  Theory of Nanomaterials Group, KU Leuven, Leuven, Belgium 
Pages
1-8
Publication year
2017
Publication date
Dec 2017
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1038/s41467-017-02016-y
ProQuest document ID
1970626903
Copyright
© 2017. 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.