Controlling tilted chiral magnetic textures in Janus Nb X Te ( X = Se, S) monolayers via magnetic field and strain engineering

Abstract While magnetic skyrmions in perpendicular magnetic anisotropy (PMA) systems are extensively studied, their realization in in-plane magnetic anisotropy (IMA) materials remains largely unexplored. Here, we demonstrate that Janus Nb X Te ( X = Se, S) monolayers host spontaneous tilted chiral textures, stabilized by substantial Dzyaloshinskii–Moriya interaction (DMI) (0.80 meV for NbSeTe, 0.59 meV for NbSTe) and intrinsic IMA. Combining first-principles calculations and atomistic spin dynamics simulations, we establish that perpendicular fields and biaxial strain independently reshape the energy landscape by tuning the competition among exchange, DMI, and anisotropy. Remarkably, while both materials spontaneously host skyrmions at zero field, NbSTe exhibits a superior field response, enabling multi-skyrmion nucleation at ∼ 0.2 T compared to ∼ 0.8 T for NbSeTe. Moreover, NbSTe sustains stability under 6% tensile strain, whereas NbSeTe undergoes topological degradation into chain-like textures. This work elucidates the stabilization mechanisms in two-dimensional (2D) IMA systems and identifies NbSTe as a robust candidate for low-power spintronic applications.