Mn_{3}3X
(X= Sn, Ge) are noncollinear antiferromagnets hosting a large anomalous
Hall effect (AHE). Weyl nodes in the electronic dispersions are believed
to cause this AHE, but their locus in the momentum space is yet to be
pinned down. We present a detailed study of the Hall conductivity tensor
and magnetization in Mn_{3}3Sn
crystals and find that in the presence of a moderate magnetic field,
spin texture sets the orientation of the kk-space
Berry curvature with no detectable in-plane anisotropy due to the
Z_6Z6
symmetry of the underlying lattice. We quantify the energy cost of
domain nucleation and show that the multidomain regime is restricted to
a narrow field window. Comparing the field dependence of AHE and
magnetization, we find that there is a distinct component in the AHE
which does not scale with magnetization when the domain walls are
erected. This so-called ‘topological’ Hall effect provides indirect
evidence for a non-coplanar spin components and real-space Berry
curvature in domain walls.
Geometrical Hall effect and momentum-space Berry curvature from spin-reversed band pairs
