Superconductivity at 40 K in Lithiation-Processed [(Fe,Al)(OH)2][FeSe]1.2 with a Layered Structure

Guobing Hu; Mengzhu Shi; Wenxiang Wang; Changsheng Zhu; Zeliang Sun; Jianhua Cui; Weizhuang Zhuo; Fanghang Yu; Xigang Luo; Xianhui Chen

doi:10.1021/acs.inorgchem.0c03686

Superconductivity at 40 K in Lithiation-Processed [(Fe,Al)(OH)₂][FeSe]_1.2 with a Layered Structure

Inorg Chem. 2021 Mar 15;60(6):3902-3908. doi: 10.1021/acs.inorgchem.0c03686. Epub 2021 Jan 22.

Authors

Guobing Hu^{1

2}, Mengzhu Shi¹, Wenxiang Wang¹, Changsheng Zhu¹, Zeliang Sun¹, Jianhua Cui¹, Weizhuang Zhuo¹, Fanghang Yu¹, Xigang Luo¹, Xianhui Chen^{1

3

4

5}

Affiliations

¹ Key Laboratory of Strongly coupled Quantum Matter Physics, Chinese Academy of Sciences, Hefei National Laboratory for Physical Sciences at Microscale, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China.
² Physical Science and Technology College, Yichun University, Yichun 336000, P. R. China.
³ Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China.
⁴ CAS Center for Excellence in Superconducting Electronics (CENSE), Shanghai 200050, P. R. China.
⁵ CAS Center for Excellence in Quantum Information and Quantum Physics, Hefei, Anhui 230026, P. R. China.

PMID: 33481576
DOI: 10.1021/acs.inorgchem.0c03686

Abstract

Exploration of new superconductors has always been one of the research directions in condensed matter physics. We report here a new layered heterostructure of [(Fe,Al)(OH)₂][FeSe]_1.2, which is synthesized by the hydrothermal ion-exchange technique. The structure is suggested by a combination of X-ray powder diffraction and the electron diffraction (ED). [(Fe,Al)(OH)₂][FeSe]_1.2 is composed of the alternating stacking of a tetragonal FeSe layer and a hexagonal (Fe,Al)(OH)₂ layer. In [(Fe,Al)(OH)₂][FeSe]_1.2, there exists a mismatch between the FeSe sublayer and the (Fe,Al)(OH)₂ sublayer, and the lattice of the layered heterostructure is quasi-commensurate. The as-synthesized [(Fe,Al)(OH)₂][FeSe]_1.2 is nonsuperconducting due to the Fe vacancies in the FeSe layer. The superconductivity with a T_c of 40 K can be achieved after a lithiation process, which is due to the elimination of the Fe vacancies in the FeSe layer. The T_c is nearly the same as that of (Li,Fe)OHFeSe although the structure of [(Fe,Al)(OH)₂][FeSe]_1.2 is quite different from that of (Li,Fe)OHFeSe. The new layered heterostructure of [(Fe,Al)(OH)₂][FeSe]_1.2 contains an iron selenium tetragonal lattice interleaved with a hexagonal metal hydroxide lattice. These results indicate that the superconductivity is very robust for FeSe-based superconductors. It opens a path for exploring superconductivity in iron-base superconductors.