Toward tunable quantum transport and novel magnetic states in Eu1−xSrxMn1−zSb2 (z < 0.05)

Magnetic semimetals are very promising for potential applications in novel spintronic devices. Nevertheless, realizing tunable topological states with magnetism in a controllable way is challenging. Here, we report novel magnetic states and the tunability of topological semimetallic states through the control of Eu spin reorientation in Eu1−xSrxMn1−zSb2. Increasing the Sr concentration in this system induces a surprising reorientation of noncollinear Eu spins to the Mn moment direction and topological semimetallic behavior. The Eu spin reorientations to distinct collinear antiferromagnetic orders are also driven by the temperature/magnetic field and are coupled to the transport properties of the relativistic fermions generated by the 2D Sb layers. These results suggest that nonmagnetic element doping at the rare earth element site may be an effective strategy for generating topological electronic states and new magnetic states in layered compounds involving spatially separated rare earth and transition metal layers. Composition phase diagram of Eu1−xSrxMn1−zSb2 on the structural and magnetic transitions, Eu–Mn moment angle α, and nontrivial Berry phase is presented. A doping of nonmagnetic Sr on Eu site breaks lattice symmetry and induces various Eu spin reorientations that are coupled to quantum transport properties of the relativistic fermions generated the 2D Sb layers. Eu1−xSrxMn1−zSb2 is therefore a new unique material platform for exploring the Dirac band tuning by magnetism. Our study suggests nonmagnetic element doping to the rare-earth element site may be an effective strategy to generate topological electronic states and new magnetic states in layered compounds involving spatially separated rare-earth and transition metal layers.