Large magneto-optical effects in the van der Waals ferrimagnet Mn3Si2Te6

Usually, traditional magneto-optical (MO) applications demand high magneto-optic figures of merit, which results in limited available materials. Tunable MO applications concerning polarization states and magnetic orientations have been proposed with the discovery of large MO effects in anisotropic low-dimensional materials. Recently, a van der Waals ferrimagnet ${\mathrm{Mn}}_{3}{\mathrm{Si}}_{2}{\mathrm{Te}}_{6}$ exhibits colossal spin orientation-dependent magnetoresistance and magnetizability by comparing these properties between the in-plane ([100]) and out-of-plane ([001]) spin configurations. Thus exploring potential MO performances of ${\mathrm{Mn}}_{3}{\mathrm{Si}}_{2}{\mathrm{Te}}_{6}$ in detail is of importance. By utilizing first-principles calculations together with group theory analyses, we systematically investigate the electronic, optical, and MO properties of ${\mathrm{Mn}}_{3}{\mathrm{Si}}_{2}{\mathrm{Te}}_{6}$. An insulator-metal transition occurs between these two spin configurations. In addition, the maximal Kerr MO rotation angles of $\ensuremath{\sim}0.{41}^{\ensuremath{\circ}}$ for the metal state are comparable to those of best-known MO materials, while the maximal Sch\"afer-Hubert rotation angle of the insulated state is nearly one-tenth. We find that the spin-orbital coupling on Te atoms makes a dominant contribution to the MO anisotropy. Based on the large MO performances and their tunability of magnetic orientation and intensity, we suggest that ${\mathrm{Mn}}_{3}{\mathrm{Si}}_{2}{\mathrm{Te}}_{6}$ could serve as a promising MO material.