In-plane strain-induced structural phase transition and interlayer antiferromagnetic skyrmions in 2H-VSe2 bilayer

The sliding and manipulation of interlayer magnetism and magnetic topological textures in two-dimensional (2D) layered materials have recently received tremendous attention. In this work, using first-principles calculations, we report a structural phase transition induced by manipulating the interlayer distance using an in-plane biaxial strain in a 2H-VSe2 bilayer. This structural phase transition is accompanied by a semiconductor-to-metal transition, in-plane-to-out-of-plane magnetization switching, and a reversal in the chirality of the Dzyaloshinskii–Moriya interaction (DMI). The binding strength of the interlayer Se2–Se3 atoms and charge density difference can serve as indicators for this structural phase transition. Furthermore, the interlayer distance of Se2–Se3 atoms can be employed as a descriptor that perfectly characterizes the degree of symmetry breaking and the magnitude of the DMI resulting from the broken spatial symmetry due to sliding. In addition, using atomistic simulations, we identify magnetic topological textures such as interlayer antiferromagnetic (AFM) frustrated bimerons and interlayer AFM skyrmions with strain. These results are beneficial for understanding and manipulating the interlayer properties of 2D layered materials through in-plane biaxial strain. In addition, the interlayer AFM frustrated bimerons and skyrmions in bilayer VSe2, which can suppress the skyrmion Hall effect due to the canceled Magnus forces in the top and bottom layers, highlight the promising applications of VSe2 in next-generation information storage devices.