ABSTRACT Although significant progress has been made in devising approaches to control magnetism and spin polarization in 2D multiferroic systems, ferroelasticity, widely recognized as a fundamental ferroic order, has received far less attention compared with ferroelectricity. In this work, we constructed a general tight‐binding (TB) model that provides a universal framework for describing the ferroelastic switching in 2D ferrimagnetic metals. Based on this model and first‐principles calculations combined with a swarm‐intelligence structure‐search strategy, we identified an example, monolayer Nb 2 CN, which simultaneously exhibits ferroelasticity, ferrimagnetism, and metallicity. Interestingly, the system can present a triply‐coupled ( S , M , ε ) switching—reversible local spin splitting ( S ), net magnetization ( M ), and ferroelastic strain ( ε ). These spin‐magnetic‐lattice couplings inevitably lead to sign reversals in anomalous transport responses such as the anomalous Hall and magneto‐optical effects. These findings not only reveal a novel magnetoelastic coupling mechanism for triply‐coupled control of magnetism and spin polarization in 2D materials but also provide a promising platform for designing multifunctional spintronic devices.
Gong et al. (2026) studied this question.