Fig. 3: Antiferromagnetic domains after zero-field cooling.

a, b Two-dimensional spatial distribution of Aʹ for k_X > 0 (a) and k_X < 0 (b) of an X-plane sample at 5 K and at 0 T after zero-field cooling. Here, Aʹ is the variation of absorption coefficient from 50 K (> T_N). E^ω is parallel to the Y axis and light wavelength is 750 nm. Dark and bright regions in (a) correspond to the L_+Y and L_−Y domains, respectively, while those in (b) correspond to the L_−Y and L_+Y domains, respectively. Scale bar below (a) is 0.2 mm. c Profiles taken along the same line from P1 to P2 in (a) (magenta) and (b) (sky blue), respectively. The difference between the two profiles at the same position corresponds to nonreciprocal directional dichroism, A_NDD.