Effect of nonparabolicity on the damping of helicons in semiconductors in the extreme quantum limit

The effect of nonparabolicity of the energy bands on the damping of helicons in semiconductors has been investigated in the extreme quantum limit of the magnetic fields so that all conduction electrons are in the ground oscillator state. Analytical expressions (corresponding to different dominant types of scattering) for the dissipative conductivity ${\sigma }_{xx}$ (whose ratio to the Hall conductivity ${\sigma }_{yx}$ determines helicon damping) have been obtained for both degenerate and nondegenerate energy distributions. Numerical results have been presented for the typical case of $n-\mathrm{InSb}$ and compared with the results for the parabolic model in the form of graphs. The nonparabolicity, in general, leads to a stronger damping of the helicons as compared to the case of parabolic bands.