  The Hall effect plays a crucial role in establishment of band theory of
solids and discovery of emergent new phases of interacting electrons such as
the topological phases of matter. Generally, the dissipationless Hall effect
requires time-reversal symmetry breaking (TRSB), where TRSB induced by external
magnetic field results in ordinary Hall effect, while TRSB caused by
spontaneous magnetization gives rise to anomalous Hall effect (AHE) which
scales with the net magnetization. The AHE is therefore not expected in
antiferromagnets with vanishing small magnetization. However, large AHE was
recently observed in certain antiferromagnets with noncolinear spin structure
and nonvanishing Berry curvature, thus opening a new area for exploration of
large AHE in antiferromagnets. Here, we report another origin of AHE in a
layered antiferromagnet, namely the domain wall (DW) skew scattering with Weyl
points near the Fermi level, in experiments for the first time. Interestingly,
the DWs form a unique periodic stripe structure with controllable periodicity
by external magnetic field, which decreases nearly monotonically from 975 nm at
0 T to 232 nm at 4 T. Electrons incident on DW with topological bound states
experience strong asymmetric scattering, leading to giant extrinsic AHE, with
the DW Hall conductivity (DWHC) at 2 K and 1.2 T even reaching a record value
of about 1.51*104 S cm-1 among bulk systems, which is two orders of magnitude
larger than the intrinsic anomalous Hall conductivity. The observation of giant
DWHC and controllable stripe DW structure in an antiferromagnet not only sets a
new paradigm for exploration of large extrinsic anomalous Hall effect, but also
provides potential applications in spintronic devices.
