Distortion effects on field-induced bimeron crystals in centrosymmetric easy-plane triangular magnets

Introduction: Noncoplanar magnetic textures such as skyrmion and bimeron crystal (BMX) phases have attracted considerable interest in frustrated magnetic systems. However, the effect of lattice distortion on the competition among multiple-Q magnetic instabilities remains unclear. Materials and methods: We investigate a distorted triangular-lattice spin model with easy-plane single-ion anisotropy under an external magnetic field by means of simulated annealing calculations. The magnetic phases are characterized through magnetization, scalar spin chirality, real-space spin textures, and spin structure factors. Results: We find that lattice distortion qualitatively reconstructs the competition among symmetry-related ordering wave vectors and modifies the stability of multiple-Q magnetic phases. Near the isotropic limit, an intermediate-field BMX phase with finite scalar spin chirality is stabilized. Increasing distortion destabilizes the BMX phase and induces transitions into distinct coplanar and noncoplanar triple-Q phases. The distortion also lifts the degeneracy among the ordering wave vectors and selectively enhances specific modulation channels. Conclusions: Our results demonstrate that lattice distortion acts as an effective control parameter for tuning field-induced multiple-Q instabilities in centrosymmetric frustrated magnets. The present study clarifies how distortion reorganizes the competition among ordering wave vectors beyond the stabilization mechanism of individual topological spin textures.