Fig. 2: Magneto-IR absorption spectra and the corresponding LL transitions.

a False color map of magneto-absorption at different energies for sample 1445. The black dash lines represent the calculated LL transition energies at different magnetic fields. The first six low-lying transitions are numbered (T1,2,...,6) in sequence of their energies. b The calculated Landau fan diagram for sample 1445. The LLs are color-coded based on their Pigeon-Brown indices. The black arrows indicate the corresponding LL transitions according to the numbering in a. c, d Same as a, b but for sample 1446. The seemingly oscillating behavior in c is due to the relatively coarse magnetic field grid (1 T step) compared to the 0.12 T step in a. All measurements are performed at 5 K.