Superconductivity in Mo5GeB2 with a tetragonal structure. (8th February 2021)

• Record Type: Journal Article
• Authors: Xu, Binjie; Lou, Zhefeng; Chen, Huancheng; Zhou, Yuxing; Chen, Qin; Chen, Shuijin; Wu, Chunxiang; Wang, Hangdong; Yang, Jinhu; Du, Jianhua; Fang, Minghu
• Is Part Of: Superconductor science & technology. Volume 34:Number 3(2021)
• Publication Date: 2021-02-08
• Subjects: Mo5GeB2 -- type II superconductor -- electron-phonon coupling -- band structure; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/1361-6668/abdf3e
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: The discovery of 39 K superconductivity in MgB2 and the recent observations of high- T c superconductivity in the high-pressured hydrides motivate ones to search for new superconductors in the compounds containing H or B light element. In this article, we chose the heavier Ge to replace the Si in the ternary borides Mo5 SiB2 with the Cr5 B3 type tetragonal structure, a relative new group borosilicate superconductors, and prepared Mo5 GeB2 polycrystalline sample. By the combination of resistivity, magnetization, and specific heat measurements and band calculations, we determine its superconducting parameters. It was found that Mo5 GeB2 is a type II superconductor, with the critical temperature T c = 5.4 K, and the Ginzburg–Landau (GL) parameter k GL (0) = 4.2. The estimated electron-phonon coupling constant λ ph (0.57) and the specific heat jump △ C e l / γ n T c (1.33) demonstrate that Mo5 GeB2 is a weak-coupling, single-gap phonon-mediated superconductor. Band calculations reveal that Mo5 GeB2 has a similar density of state (DOS) near Fermi energy to that of Mo5 SiB2 with the same T c, but smaller than that Mo5 PB2 with T c = 9.2 K.