Protonation induced high-Tc phases in iron-based superconductors evidenced by NMR and magnetization measurements

Yi Cui; Gehui Zhang; Haobo Li; Hai Lin; Xiyu Zhu; Hai-Hu Wen; Guoqing Wang; Jinzhao Sun; Mingwei Ma; Yuan Li; Dongliang Gong; Tao Xie; Yanhong Gu; Shiliang Li; Huiqian Luo; Pu Yu; Weiqiang Yu

doi:10.1016/j.scib.2017.12.009

Protonation induced high-T_c phases in iron-based superconductors evidenced by NMR and magnetization measurements

Sci Bull (Beijing). 2018 Jan 15;63(1):11-16. doi: 10.1016/j.scib.2017.12.009. Epub 2017 Dec 10.

Authors

Yi Cui¹, Gehui Zhang¹, Haobo Li², Hai Lin³, Xiyu Zhu³, Hai-Hu Wen³, Guoqing Wang⁴, Jinzhao Sun⁴, Mingwei Ma⁴, Yuan Li⁵, Dongliang Gong⁶, Tao Xie⁶, Yanhong Gu⁶, Shiliang Li⁷, Huiqian Luo⁸, Pu Yu⁹, Weiqiang Yu¹⁰

Affiliations

¹ Department of Physics, Renmin University of China, Beijing 100872, China.
² State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China.
³ Center for Superconducting Physics and Materials, National Laboratory of Solid State Microstructures and Department of Physics, Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China.
⁴ International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China.
⁵ International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China.
⁶ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China.
⁷ Collaborative Innovation Center of Quantum Matter, Beijing 100871, China; Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, China.
⁸ Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
⁹ State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China; Collaborative Innovation Center of Quantum Matter, Beijing 100871, China. Electronic address: [email protected].
¹⁰ Department of Physics, Renmin University of China, Beijing 100872, China. Electronic address: [email protected].

PMID: 36658911
DOI: 10.1016/j.scib.2017.12.009

Abstract

Chemical substitution during growth is a well-established method to manipulate electronic states of quantum materials, and leads to rich spectra of phase diagrams in cuprate and iron-based superconductors. Here we report a novel and generic strategy to achieve nonvolatile electron doping in series of (i.e. 11 and 122 structures) Fe-based superconductors by ionic liquid gating induced protonation at room temperature. Accumulation of protons in bulk compounds induces superconductivity in the parent compounds, and enhances the T_c largely in some superconducting ones. Furthermore, the existence of proton in the lattice enables the first proton nuclear magnetic resonance (NMR) study to probe directly superconductivity. Using FeS as a model system, our NMR study reveals an emergent high-T_c phase with no coherence peak which is hard to measure by NMR with other isotopes. This novel electric-field-induced proton evolution opens up an avenue for manipulation of competing electronic states (e.g. Mott insulators), and may provide an innovative way for a broad perspective of NMR measurements with greatly enhanced detecting resolution.

Keywords: Ion liquid gating; Iron-based superconductors; NMR; Protonation.