Anisotropic free carrier voigt effect in cubic semiconductors

Abstract

The free carrier Voigt effect is calculated for cubic semiconductors with free carriers having anisotropic effective masses using a Drude-Zener model. Particular attention is paid to the nature of the approximation involved in only keeping terms to the square of the magnetic field for evaluating the phase shift. Application is made to the case of mass ellipsoids in the [111]-directions and the orientational dependence of the Voigt effect for a typical sample of n-type Ge is presented for a configuration and conditions of experimental interest, namely, for a thin sample coinciding with the [100]-plane. It is shown that the infrared Voigt effect has limited application in that for realistic samples of Ge and other prospective materials, the Voigt effect will be rather small for usual working frequencies and available magnetic fields. Another interesting but less feasible experiment is noted in which, for certain magnetic field directions, with incident radiation polarized either parallel or perpendicular to the magnetic field, there occurs, in principle, a component of transmitted radiation respectively perpendicular or parallel to the magnetic field. Unfortunately this effect is not discernible for the typical sample of Ge under the experimental conditions considered.