Emergent Canted Antiferromagnetism from Frustrated Charge Transfer in Half-Metal Candidate MnPSe3

Abstract

Layered van der Waals magnetic materials exhibiting half-metallicity represent promising platforms for spintronic applications. The transition-metal phosphorus trichalcogenide MnPSe3 has been theoretically predicted to host an intrinsic ferromagnetic half-metallic state in its monolayer under sufficient carrier doping. However, realizing experimentally accessible half-metallicity in this system poses a great challenge, as the controversy over the magnetic state of organic-ion-intercalated MnPSe3 crystals, which are commonly regarded as doped monolayers, remains unresolved. Here, we resolve this controversy by identifying a canted antiferromagnetic ground state in pyrrolidinium-intercalated MnPSe3, which originates from the combined effects of competition between direct Mn–Mn antiferromagnetic exchange and Mn–Se–Mn ferromagnetic superexchange, as well as enhanced single-ion anisotropy. X-ray photoelectron spectroscopy and X-ray absorption near-edge structure reveal multiple charge transfer pathways that lead to frustrated charge redistribution, diminishing the enhancement of ferromagnetic superexchange and yielding balanced competing interactions. First-principles calculations further validate that this canted antiferromagnetic state is an intermediate phase during the doping-driven antiferromagnetic-to-ferromagnetic transition. Our work not only clarifies the longstanding magnetic state controversy but also advances mechanistic understanding of charge transfer in this system, paving the way for the rational design of half-metallic van der Waals magnets toward practical spintronic devices.