Large Magnetoresistance and Nontrivial Berry Phase in Nb3Sb Crystals with A15 Structure

Abstract

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 ρ_xx (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.