Fig. 5: Theoretical reproduction of magneto-infrared spectra of LaAlSi.
a Comparison of optical conductivity in different extents of Landau level broadening. (i) and (ii): the schematic drawings of Landau levels with negligible (\(\varGamma \sim 0\)) and considerable (\(\varGamma \gg 0\)) energy broadening, respectively. In a quantum-limit system, T0 is intrinsically contributed by the transition of \(-1\to +0\) (red solid arrow), and the transition of \(-0\to +1\) (red dashed arrow) is generally forbidden because of the Pauli blocking effect. The energy broadening of \(-0\) Landau level and thermal excitation can partially allow \(-0\to +1\). Calculated from optical conductivity spectra (iii) and (iv), the spectral weight (v) of T0 is significantly enhanced with an increased extent of broadening. b Simulation of spectral feature amplified by the bulk plasma. In panel (i), two optical conductivity spectra possess identical Drude components, but the Lorentz components with the same spectral weight are located at (pink curve) and far away from (blue curve) the plasma energy. Panel (ii): corresponding reflectivity spectra, indicating that the dielectric coupling with the plasma edge can significantly amplify the spectral feature of the Lorentz component. c Theoretical magneto-infrared spectra calculated based on the Kubo formula and Drude-Lorentz function.
