Magnetic switching in antiferromagnets relies on Néel spin-orbit torque (NSOT), which originates from an electric-field-induced staggered spin polarization of itinerant electrons. In collinear antiferromagnets, such a response requires the spin susceptibility to be odd under combined space-time inversion symmetry ($\mathcal{PT}$), and is conventionally attributed to symmetric scattering processes. Here, we identify an additional $\mathcal{PT}$-odd spin polarization in the linear response regime, generated by the interplay between antisymmetric higher-order scattering processes and the impurity-induced correction to the spin expectation value. Its compact weak-disorder form is controlled by band geometry, or the anomalous spin polarizability (ASP) of Bloch electrons, which converts an otherwise $\mathcal{PT}$-even susceptibility into a staggered spin polarization. Using a minimal model of tetragonal $\mathrm{CuMnAs}$, we show that the resulting anomalous skew-scattering contribution can be comparable to, and for sufficiently strong impurity effects in the present model can exceed, the conventional symmetric scattering (Drude) contribution. Our results identify a new band-geometry-assisted disorder mechanism for NSOT and clarify a route by which impurity scattering can enhance electrical control of antiferromagnets.

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• Quantum geometry
• Spin-orbit torque
• Spintronics
• Antiferromagnets
• Spin
• Boltzmann theory