Large unsaturated transverse and negative longitudinal magnetoresistance in the compensated semimetal MoGe2

We report the experimental results of magnetotransport on the single crystal MoGe2, which was theoretically predicated to be a topological insulator. The resistivity of MoGe2 exhibits a metallic behavior at zero field, while with magnetic fields applied along the z axis and perpendicular to current, MoGe2 presents an upturn resistivity behavior and unsaturated quadratic large magnetoresistance (MR). The analysis of Hall effect shows that MoGe2 is a compensated semimetal with high mobilities at low temperatures, which is the origin of resistivity upturn and unsaturated large MR. As magnetic fields parallel to current, MoGe2 shows a weak antilocalization effect at low fields and a pronounced negative MR at higher fields, which is analogous to the picture of the Adler-Bell-Jackiw axial anomaly. Our results indicate that MoGe2 is a topological semimetal rather than a topological insulator, and will encourage further theoretical and experimental investigations on this compound.