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Compounds with the A15 structure have attracted extensive attention due to their superconductivity and nontrivial topological band structures. We have successfully grown Nb3Sb single crystals with the A15 structure and systematically measured the longitudinal resistivity, Hall resistivity and quantum oscillations in magnetization. Similar to other topological trivial/nontrivial semimetals, Nb3Sb exhibits large magnetoresistance (MR) at low temperatures (717%, 2 K and 9 T), unsaturating quadratic field dependence of MR and up-turn behavior in ρxx(T) curves under magnetic field, which is considered to result from a perfect hole-electron compensation, as evidenced by the Hall resistivity measurements. The nonzero Berry phase obtained from the de-Hass van Alphen (dHvA) oscillations demonstrates that Nb3Sb is topologically nontrivial. These results indicate that Nb3Sb superconductor is also a semimetal with large MR and nontrivial Berry phase. This indicates that Nb3Sb may be another platform to search for the Majorana zero-energy mode. [ABSTRACT FROM AUTHOR]

We performed calculations of the electronic band structure and the Fermi surface, measured the longitudinal resistivity ρxx(T,H), Hall resistivity ρxy(T,H), and magnetic susceptibility as a function of temperature at various magnetic fields for VAs2 with a monoclinic crystal structure. The band structure calculations show that VAs2 is a nodal-line semimetal when spin-orbit coupling is ignored. The emergence of a minimum at around 11 K in ρxx(T) measured at H = 0 demonstrates that some additional magnetic impurities (V4+, S = 1/2) exist in VAs2 single crystals, inducing Kondo scattering, evidenced by both the fitting of ρxx(T) data and the susceptibility measurements. It is found that a large positive magnetoresistance (MR) reaching 649% at 10 K and 9 T, its nearly quadratic field dependence, and a field-induced up-turn behavior of ρxx(T) also emerge in VAs2, although MR is not so large due to the existence of additional scattering compared with other topological nontrivial/trivial semimetals. The observed properties are attributed to a perfect charge-carrier compensation, which is evidenced by both the calculations relying on the Fermi surface and the Hall resistivity measurements. These results indicate that the compounds containing V (3d3 4s2) element can be as a platform for studying the influence of magnetic impurities to the topological properties. [ABSTRACT FROM AUTHOR]

We performed calculations of the electronic band structure and the Fermi surface, measured the longitudinal resistivity ρxx(T,H), Hall resistivity ρxy(T,H), and magnetic susceptibility as a function of temperature at various magnetic fields for VAs2 with a monoclinic crystal structure. The band structure calculations show that VAs2 is a nodal-line semimetal when spin-orbit coupling is ignored. The emergence of a minimum at around 11 K in ρxx(T) measured at H = 0 demonstrates that some additional magnetic impurities (V4+, S = 1/2) exist in VAs2 single crystals, inducing Kondo scattering, evidenced by both the fitting of ρxx(T) data and the susceptibility measurements. It is found that a large positive magnetoresistance (MR) reaching 649% at 10 K and 9 T, its nearly quadratic field dependence, and a field-induced up-turn behavior of ρxx(T) also emerge in VAs2, although MR is not so large due to the existence of additional scattering compared with other topological nontrivial/trivial semimetals. The observed properties are attributed to a perfect charge-carrier compensation, which is evidenced by both the calculations relying on the Fermi surface and the Hall resistivity measurements. These results indicate that the compounds containing V (3d3 4s2) element can be as a platform for studying the influence of magnetic impurities to the topological properties. [ABSTRACT FROM AUTHOR]