Magnetochiral dichroism in a collinear antiferromagnet MnTiO₃ with zero magnetization

Symmetry breaking induces specific optical effects. Magnetochiral dichroism (MChD) - nonreciprocal directional asymmetry in the propagation of unpolarized light - has been found to be induced by simultaneous breaking of the space-inversion and time reversal symmetries. After the first discovery [1], it has been established that net magnetization along with the light path causes MChD in various chiral magnets. In contrast, MChD in antiferromagnets without magnetization is less explored.
Here we report the MChD in a collinear antiferromagnet MnTiO₃ in the absence of magnetization. We observed some asymmetry in the absorption coefficient between the light beams propagating parallel and antiparallel to the net staggered magnetization. Exploiting the linear magnetoelectric coupling [2], we also demonstrate the electric-field and magnetic-field induced switching of absorbance in MnTiO₃. In our presentation, we will propose the microscopic description of the origin of the MChD in MnTiO₃ from the viewpoint of local symmetry on each Mn site.
[1] G. Rikken and E. Raupach, Phys. Rev. E 58, 5081 (1998).
[2] N. Mufti et al., Phys. Rev. B 83, 104416 (2011).