Highly tunable magnetism and giant electrical control in VSeTe lateral heterostructures

The engineering of magnetic anisotropy in two-dimensional (2D) materials is crucial for the development of high-density, low-power spintronic devices. Here, we propose an efficient strategy to achieve superior magnetic tunability by constructing an in-plane lateral heterostructure (LH-VSeTe) from Janus VSeTe monolayers. We demonstrate that this covalently bonded heterostructure is not only energetically favorable and dynamically stable but also exhibits robust intrinsic ferromagnetism. Our results show that both biaxial strain and hole doping can effectively control their magnetic anisotropy energy, inducing a spin reorientation from in-plane to perpendicular magnetic anisotropy by changing the spin-orbit coupling interactions of Te atoms. Most significantly, the LH-VSeTe structure exhibits a giant voltage-controlled magnetic anisotropy (VCMA) coefficient of approximately 481 fJ/Vm, which is over an order of magnitude larger than that of its 2H counterpart. This exceptional VCMA effect stems from the unique charge rearrangement and alternation of electronic occupations at the lateral interface under an electric field. Our work establishes in-plane heterostructuring as a powerful paradigm for designing 2D magnets with enhanced functionalities and identifies LH-VSeTe as a prime candidate for future spintronic applications.