Strong-Coupling Superconductivity with $T_c$ $\sim$ 10.8 K Induced by P Doping in the Topological Semimetal Mo$_5$Si$_3$

Bin-Bin Ruan; Jun-Nan Sun; Yin Chen; Qing-Song Yang; Kang Zhao; Meng-Hu Zhou; Ya-Dong Gu; Ming-Wei Ma; Gen-Fu Chen; Lei Shan; Zhi-An Ren

doi:10.1007/s40843-022-2102-8

paper

Strong-Coupling Superconductivity with $T_{c}$ $\sim$ 10.8 K Induced by P Doping in the Topological Semimetal Mo $_{5}$ Si $_{3}$

arXiv:2208.02392 · doi:10.1007/s40843-022-2102-8

Abstract

By performing P doping on the Si sites in the topological semimetal Mo $_{5}$ Si $_{3}$ , we discover strong-coupling superconductivity in Mo $_{5}$ Si $_{3 - x}$ P $_{x}$ (0.5 $\leq$ $x$ $\leq$ 2.0). Mo $_{5}$ Si $_{3}$ crystallizes in the W $_{5}$ Si $_{3}$ -type structure with space group of $I 4/ m c m$ (No. 140), and is not a superconductor itself. Upon P doping, the lattice parameter $a$ decreases while $c$ increases monotonously. Bulk superconductivity is revealed in Mo $_{5}$ Si $_{3 - x}$ P $_{x}$ (0.5 $\leq$ $x$ $\leq$ 2.0) from resistivity, magnetization, and heat capacity measurements. $T_{c}$ in Mo $_{5}$ Si $_{1.5}$ P $_{1.5}$ reaches as high as 10.8 K, setting a new record among the W $_{5}$ Si $_{3}$ -type superconductors. The upper and lower critical fields for Mo $_{5}$ Si $_{1.5}$ P $_{1.5}$ are 14.56 T and 105 mT, respectively. Moreover, Mo $_{5}$ Si $_{1.5}$ P $_{1.5}$ is found to be a fully gapped superconductor with strong electron-phonon coupling. First-principles calculations suggest that the enhancement of electron-phonon coupling is possibly due to the shift of the Fermi level, which is induced by electron doping. The calculations also reveal the nontrivial band topology in Mo $_{5}$ Si $_{3}$ . The $T_{c}$ and upper critical field in Mo $_{5}$ Si $_{3 - x}$ P $_{x}$ are fairly high among pseudobinary compounds. Both of them are higher than those in NbTi, making future applications promising. Our results suggest that the W $_{5}$ Si $_{3}$ -type compounds are ideal platforms to search for new superconductors. By examinations of their band topologies, more candidates for topological superconductors can be expected in this structural family.

arXiv comment15 pages, 5 figures. Supplementary Information availabe at the corresponding DOI

Strong-Coupling Superconductivity with $T_{c}$ $\sim$ 10.8 K Induced by P Doping in the Topological Semimetal Mo $_{5}$ Si $_{3}$

Abstract

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Strong-Coupling Superconductivity with Tc​ ∼ 10.8 K Induced by P Doping in the Topological Semimetal Mo5​Si3​

Abstract

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Cited by in corpus (2)

Strong-Coupling Superconductivity with $T_{c}$ $\sim$ 10.8 K Induced by P Doping in the Topological Semimetal Mo $_{5}$ Si $_{3}$