Large negative magnetoresistance in the antiferromagnetic rare-earth dichalcogenide EuTe2

We report the synthesis and characterization of a rare-earth dichalcogenide ${\mathrm{EuTe}}₂$. An antiferromagnetic transition was found at ${T}_{\mathrm{N}}=11\phantom{\rule{0.28em}{0ex}}\mathrm{K}$. The antiferromagnetic order can be tuned by an applied magnetic field to access a first-order spin-flop transition and a spin-flip transition. These transitions are associated with a large negative magnetoresistance with a change of magnitude of resistivity over five orders. Magnetic susceptibility, heat capacity, and Hall coefficient measurements reveal that the moments of ${\mathrm{Eu}}²⁺$ align along the $c$ axis and holes are the majority carriers. Furthermore, density functional theory calculations demonstrate that the carriers near the Fermi surface mainly originate from the Te $5p$ orbitals and the magnetism is dominated by localized electrons from the Eu $4f$ orbitals. Our results suggest that ${\mathrm{EuTe}}₂$ is an $A$-type antiferromagnetic material with large negative magnetoresistance.