Chirality‐Selected Noncollinear Antiferromagnetic State

Abstract The topological noncollinear antiferromagnet (AFM) Mn 3 Sn exhibits a giant anomalous Hall conductance (AHC) originating from its nonvanishing Berry curvature. Conventionally, the two AHC states are regarded as time‐reversal pairs coupled to the magnetic octupole moment, and their control has relied on reversing this moment by external magnetic fields or electric currents. Here, an alternative mechanism is demonstrated—the chirality‐selected noncollinear antiferromagnetic state—in which the AHC polarity is defined by the vector spin chirality (VSC) of the Kagome lattice. By constructing Mn 3 Sn/Pt heterostructures, a Fert–Levy–type Dzyaloshinskii–Moriya interaction (DMI) is introduced that sets the lattice chirality. The induced DMI changes the VSC from counterclockwise (CCW) to clockwise (CW), resulting in a corresponding inversion of the AHC sign. This behavior is confirmed by symmetry analysis and atomistic simulations that link the polarity inversion to the competition between DMI energy and intrinsic anisotropy. These findings establish a chirality‐defined route for controlling noncollinear antiferromagnetic order and highlight DMI engineering as a powerful means of tailoring Berry‐curvature‐driven transport in AFMs.