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arXiv · 2111.06010

NbReSi: A Noncentrosymetric Superconductor with Large Upper Critical Field

H. Su·T. Shang·F. Du·C. F. Chen·H. Q. Ye·X. Lu·C. Cao·M. Smidman·H. Q. Yuan
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Abstract

We report the discovery of superconductivity in noncentrosymmetric NbReSi, which crystallizes in a hexagonal ZrNiAl-type crystal structure with space group $P\bar{6}2m$ (No.~189). Bulk superconductivity, with $T_c$ = 6.5 K was characterized via electrical-resistivity, magnetization, and heat-capacity measurements. The low-temperature electronic specific heat suggests a fully gapped superconducting state in NbReSi, while a large upper critical field of $μ_0H_\mathrm{c2}(0)$ $\sim$ 12.6 T is obtained, which is comparable to the weak-coupling Pauli limit. The electronic band-structure calculations show that the density of states at the Fermi level are dominated by Re and Nb $d$-orbitals, with a sizeable band splitting induced by the antisymmetric spin-orbit coupling. NbReSi represents another candidate material for revealing the puzzle of time-reversal symmetry breaking observed in some Re-based superconductors and its relation to the lack of inversion symmetry.

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H. Su, T. Shang, F. Du, C. F. Chen, H. Q. Ye, X. Lu, C. Cao, M. Smidman, H. Q. Yuan. 2021-11-11. NbReSi: A Noncentrosymetric Superconductor with Large Upper Critical Field. https://doi.org/10.1103/physrevmaterials.5.114802

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