Fig. 3: Reflectance and optical conductivity in magnetic field.

a Reflectance ratios of Mn₃Si₂Te₆ as a function of magnetic field. Inset: close-up view of the reflectance ratio spectra. All data are collected at 5.5 K. As we discuss in the main text, the appearance of new features at high fields is entirely due to changes in the electronic background and is almost totally decoupled from the lattice. b Reflectance as a function of magnetic field, back-calculated from the base temperature data in Fig. 2 and the ratios in a. Inset: close-up view of the reflectance spectra. c Optical conductivity of Mn₃Si₂Te₆ as a function of magnetic field, calculated from a Kramers–Kronig analysis of the reflectance in b. Inset: close-up view of the optical conductivity in the far infrared range.