Field-induced metal-to-insulator transition and colossal anisotropic magnetoresistance in a nearly Dirac material EuMnSb2

Realizing applicably appreciated spintronic functionalities basing on the coupling between charge and spin degrees of freedom is still a challenge. For example, the anisotropic magnetoresistance (AMR) effect can be utilized to read out the information stored in magnetic structures. However, the application of AMR in antiferromagnet-based spintronics is usually hindered by the small AMR value. Here, we discover a colossal AMR with its value reaching 1.84 × 106% at 2 K, which stems from the field-induced metal-to-insulator transition (MIT), in a nearly Dirac material EuMnSb2. Density functional theory calculations identify a Dirac-like band around the Y point that depends strongly on the spin–orbit coupling and dominates the electrical transport. The indirect band gap at the Fermi level evolves with magnetic structure of Eu2+ moments, consequently giving rise to the field-induced MIT and the colossal AMR. Our results suggest that the antiferromagnetic topological materials can serve as a fertile ground for spintronics applications.