Magnetotransport and Shubnikov–de Haas oscillations of a type-II nodal-line semimetal candidate Mg₃Bi₂

Mg₃Bi₂ is a candidate type-II nodal-line semimetal (a novel category of topological semimetals). However, exotic transport properties of Mg₃Bi₂ single crystal are yet to be elucidated. Herein, we report the magnetotransport properties of an n-type Mg₃Bi₂ single crystal that was grown from a melt. The results revealed that the single crystal exhibited a very large nonsaturating magnetoresistance (5000%) under an 8 T field, significantly exceeding those of polycrystals. We explored its Shubnikov–de Haas oscillations, which revealed a small effective mass as well as a nontrivial phase shift, suggesting Dirac-fermion features in Mg₃Bi₂. We confirmed that the electron mobility reached 10000 cm²/Vs by analyzing the Hall resistivity and magnetoresistance based on a two-carrier model. Overall, these results are critical to elucidating the electronic structure and transport properties of Mg₃Bi₂.