Correlation of Tunable CoSi4 Tetrahedron with the Superconducting Properties of LaCoSi

Zhengwen He; Yuzhu Song; Kaiyao Zhou; Shibin Guo; Junkun Wu; Congling Yin; Zhongnan Guo; Lunhua He; Qingzhen Huang; Laifeng Li; Rongjin Huang; Jiangang Guo; Xianran Xing; Jun Chen

doi:10.1021/acs.inorgchem.1c01369

Correlation of Tunable CoSi₄ Tetrahedron with the Superconducting Properties of LaCoSi

Inorg Chem. 2021 Aug 2;60(15):10880-10884. doi: 10.1021/acs.inorgchem.1c01369. Epub 2021 Jul 21.

Authors

Zhengwen He¹, Yuzhu Song¹, Kaiyao Zhou², Shibin Guo³, Junkun Wu⁴, Congling Yin⁴, Zhongnan Guo⁵, Lunhua He⁶, Qingzhen Huang⁷, Laifeng Li³, Rongjin Huang³, Jiangang Guo², Xianran Xing¹, Jun Chen¹

Affiliations

¹ Beijing Advanced Innovation Center for Materials Genome Engineering and Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China.
² Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, P.O. Box 603, Beijing 100190, China.
³ Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100049, China.
⁴ MOE Key Laboratory of New Processing Technology for Nonferrous Metal and Materials, Guangxi Key Laboratory of Optic and Electronic Materials and Devices, College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, P. R. China.
⁵ Department of Chemistry, School of Chemistry and Biological Engineering, University of Science and Technology Beijing, Beijing 100083, China.
⁶ Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China.
⁷ NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102, United States.

PMID: 34288645
DOI: 10.1021/acs.inorgchem.1c01369

Abstract

It is known that as the FeAs₄ tetrahedron in the Fe-based superconductor is close to the regular tetrahedron, critical temperature (T_c) can be greatly increased. Recently, a Co-based superconductor of LaCoSi (4 K) with "111" structure was found. In this work, we improve the T_c of LaCoSi through structural regulation. T_c can be increased by the chemical substitution of Co by Fe, while the superconductivity is suppressed by the Ni substitution. The combined analysis of neutron and synchrotron X-ray powder diffractions reveals that the change of the Si-Co-Si bond angles of the CoSi₄ tetrahedron is possibly responsible for the determination of superconducting properties. The Fe chemical substitution is favorable for the formation of the regular tetrahedron of CoSi₄. The present new Co-based superconductor of LaCoSi provides a possible method to enhance the superconductivity performance of the Co-based superconductors via controlling Co-based tetrahedra similar to those well established in the Fe-based superconductors.