Hot electron faraday-effect and non-equivalent inter-valley transfer in n-type Ge

I.R. Faraday rotation measurements have been performed on n-type Ge at 200K and 300K up to electric field strength of $\text{5.5kV}\text{cm}$. The decrease in rotation is interpreted in terms of an increase in average effective mass of the electrons. Both, nonparabolicity of the conduction band and transfer of electrons to satellite valleys have to be considered for the interpretation of the results.