  High harmonic generation (HHG) is a striking phenomenon, which reflects the
ultrafast dynamics of electrons. Recently, it has been demonstrated that HHG
can be used to reconstruct not only the energy band structure but also the
geometric structure characterized by the Berry curvature. Here, we numerically
investigate HHG arising from electrons coupled with a topological spin texture
in a spin scalar chiral state where time reversal symmetry is broken. In this
system, a sign change in scalar chirality alters the sign of the Berry
curvature while keeping the energy band structure unchanged, allowing us to
discuss purely geometrical effects on HHG. Notably, we found that, when the
optical frequency is significantly lower than the energy gap, the sign of
scalar chirality largely affects the longitudinal response parallel to the
optical field rather than the transverse response. Our analysis suggests that
this can be attributed to interband currents induced by the recombination of
electron-hole pairs whose real-space trajectories are modulated by the
anomalous velocity term.
