2026/07/18 by Alberto M. Ruiz, Cuiju Yu, Diego López-Alcalá +3 · 1 voice
#cond-mat.mtrl-sci #cond-mat.mes-hall
Altermagnetism is a collinear magnetic state characterized by momentum-dependent spin splitting in fully compensated materials. While widely investigated in systems governed by three- or two-dimensional exchange interactions, its extension to quasi-one-dimensional magnets remains almost unexplored. Focusing on the experimentally established AgCrP2S6 van der Waals magnet, we demonstrate that antiferromagnetic chains embedded in a two-dimensional lattice provide a general route to altermagnetism. Combining first-principles calculations and spin-space-group analysis, we show that out-of-plane symmetry breaking can generate a nonrelativistic d-wave spin splitting. An external out-of-plane electric field validates this mechanism, where the induced splitting increases linearly with field strength and reverses sign with field direction. We rationalize such behaviour by constructing an effective tight-binding model, which links the altermagnetic response to anisotropic third-neighbor interchain hoppings. Additionally, we show that Janus substitution also induces a d-wave spin texture, while ferroelectric interfacing with CuInP2S6 enables polarization-controlled spin-split bands in a fully compensated ferrimagnetic state. Our results establish quasi-one-dimensional antiferromagnets as building blocks for altermagnetism.