X-Type Antiferromagnets

Magnetically ordered materials reveal various types of magnetic moment alignment that affects their functional properties. This makes the exploration of unconventional magnetic orderings promising for the discovery of new physical phenomena and spintronic applications. Here, we introduce cross-chain antiferromagnets, dubbed X-type antiferromagnets, as an uncharted class of magnetically ordered crystals, where the stacking of two magnetic sublattices form an orthogonal pattern of intersecting atomic chains. These largely unexplored X-type antiferromagnets reveal unique spin-dependent transport properties that are not present in conventional magnets. Using $\beta$-Fe2PO5 as a representative example of such X-type antiferromagnets, we predict the emergence of sublattice-selective spin-polarized transport, where one magnetic sublattice is conducting, while the other is not. As a result, spin torque can be exerted solely on a single sublattice, leading to unconventional ultrafast dynamics of the N\`eel vector capable of deterministic switching of the antiferromagnetic domains. Our work uncovers a previously overlooked type of magnetic moment alignment in antiferromagnets and reveals sublattice-selective physical properties promising for high-performance spintronic applications.