Interface-driven magnetic reconfiguration in lateral MXene heterostructures

The lateral heterostructure of two-dimensional (2D) materials provides a powerful route for engineering emergent electronic and magnetic functionalities through atomically sharp interfaces. In this work, we present a comprehensive multiscale investigation of lateral MXene heterostructures by combining density functional theory (DFT), Heisenberg spin modeling, and finite-temperature Monte Carlo (MC) simulations. A series of lateral junctions with distinct compositional motifs (1-1, 2-2, 1-3, and 3-1) are systematically constructed, and their structural stability is confirmed through cohesive and formation energy analyses, supported by interfacial charge redistribution. Our results demonstrate that lateral interfacing fundamentally modifies magnetic ground states compared to pristine MXenes, with interfacial exchange interactions acting as the dominant factor governing magnetic ordering. The competition between intra-domain and inter-domain couplings gives rise to a diverse range of magnetic phases, including ferromagnetic, antiferromagnetic, ferrimagnetic, and nonmagnetic configurations, depending on the composition and junction geometry. Electronic structure analysis reveals that transition-metal d-orbital hybridization and interfacial charge transfer play a key role in stabilizing the metallicity and spin polarization, establishing a direct link between electronic states and magnetic interactions. Finite-temperature MC simulations show that magnetic transition temperatures span a broad range and demonstrate strong tunability of magnetic behavior. Notably, interfacial exchange coupling is identified as a dominant and tunable parameter that enables magnetic phase reconfiguration beyond the limits of pristine MXenes. This interface-driven mechanism provides a pathway for designing low-dimensional magnetic systems with programmable spin-dependent properties. Overall, this study establishes lateral MXene heterostructures as a versatile platform for tailoring magnetism in 2D systems and provides a predictive framework for interface-controlled spintronic materials.