High-Pressure Crystal Growth, Superconducting Properties, and Electronic Band Structure of Nb2P5

Orthorhombic (space group: Pnma) Nb2P5 is a high-pressure phase that is quenchable to ambient pressure, which could be viewed as zigzag P8 chain-inserted NbP2. We report herein the high-pressure crystal growth of Nb2P5 and the discovery of its superconducting transition at Tc similar to 2.6 K. The electrical resistivity, magnetization, and specific heat capacity measurements on the high-quality crystal unveiled a conventional type-II weakly coupled s-wave nature of the superconductivity, with the upper critical field Hc2(0) similar to 0.5 T, the electron-phonon coupling strength.ep similar to 0.5-0.8, and the Ginzburg-Landau parameter. similar to 100. The ab initio calculations on the electronic band structure unveiled nodal-line structures protected by different symmetries. The one caused by band inversion, for example, on the G-X and U-R paths of the Brillouin zone, likely could bring nontrivial topology and hence a possible nontrivial surface state on the surface. The surface states on the (100), (010), and (110) surfaces were also calculated and discussed. The discovery of the phosphorus-rich Nb2P5 superconductor would be instructive for the design of more metal phosphide superconductors, which might host unconventional superconductivity or potential technical applications.