probability increases. Hence we observe the enhancement of the amplitude of the peak in conductivity upon shifting the Fermi level and is a probable cause of the experimentally observed peak.

![(a) Decomposition of the the total inter-band optical conductivity into individual band transitions. Transitions from bands (39, 40) to (41, 42) result in the peak at 200 cm$^{-1}$ whereas transitions from bands (37, 38) to (39, 40) is the origin of the peak at 950 cm$^{-1}$. (b) Similar decomposition assuming a 10$^{\circ}$ canted AFM order in the band structure.[]{data-label="fig:dec"}](S1_dec.png "fig:"){width="48.00000%"}\
![(a) Decomposition of the the total inter-band optical conductivity into individual band transitions. Transitions from bands (39, 40) to (41, 42) result in the peak at 200 cm$^{-1}$ whereas transitions from bands (37, 38) to (39, 40) is the origin of the peak at 950 cm$^{-1}$. (b) Similar decomposition assuming a 10$^{\circ}$ canted AFM order in the band structure.[]{data-label="fig:dec"}](S1_dec_canted.png "fig:"){width="48.00000%"}

It is interesting to note that in the context of the conductivity calculated from the band structure with canted AFM order, the origin of the peak at 200 cm$^{-1}$ is somewhat different than in the context of the uncanted structure, despite appearing at a similar energy scale. A decomposition into 