Multi-Q magnets consist of superposed spin-density waves with distinct magnetic modulation vectors, enabling a wide range of magnetic orders depending on their combination. Among them, topologically nontrivial spin textures, such as a magnetic skyrmion, have been extensively studied owing to the emergence of topological Hall effects induced by real-space scalar spin chirality. Contrary to this expectation, we theoretically investigate another route to enhancing the Hall response under a topologically trivial double-Q spin textures with neither net scalar spin chirality nor a nonzero skyrmion number. Despite the cancellation of the scalar spin chirality, the double-Q magnetism exhibits a Hall response significantly larger than that of the ferromagnetic phase with a nonmonotonic dependence on the uniform magnetization, which is in stark contrast with a ferromagnetic state and a single-Q spiral state. Analyzing the multiorbital Kondo lattice model, we show that orbital hybridization induced by the double-Q superstructure result in a proliferation of Berry curvature hot spots in $\mathbf{k}$ space, thereby giving rise to a large anomalous Hall effect (AHE). This mechanism accounts for the observed giant AHE in ${\mathrm{GdRu}}_2{\mathrm{Si}}_2$ and ${\mathrm{GdRu}}_2{\mathrm{Ge}}_2$, thereby highlighting topologically trivial double-Q spin textures as promising spintronic materials.

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• Anomalous Hall effect
• Berry curvature
• Electronic structure
• Materials
• Spin texture
• Noncollinear magnets
• Kondo lattice model