Quantum-mechanical features of helicon wave propagation in n-type InSb

Abstract

The role of quantum-mechanical oscillatory relaxation time and high-frequency conductivity in the presence of a strong magnetic field has been studied. Accounting for the oscillatory relaxation process and high-frequency conductivity, the dispersion equation for helicon wave propagation has been derived. The dispersion equation thus obtained has been used to construct the refractive-index surfaces. The effect of magnetic field and the helicon wave frequency on the refractive-index surfaces is shown to introduce deformation which offsets the focusing of the propagating helicon waves. The focusing and the interference of the helicon wave along the magnetic-field direction have been discussed in terms of the energy gap between the Fermi energy and the various Landau levels. The analysis of the dispersion equation for real and complex k has been carried out to study the role of convective instability in the InSb sample. The relative growth rate of helicon waves propagating through InSb at 4.2°K has been computed for different values of the applied-magnetic-field strength. It is shown that the helicon waves propagating through the sample undergo a typical oscillation. These oscillations can be used as a diagnostic for determining various parameters of the sample. © 1978 The American Physical Society.