Abstract
The infra-red Faraday effect has been measured in p-type Si, GaSb and GaAs. These and previous measurements on p-type germanium are interpreted in terms of contributions due to light and heavy holes and intervalence band transitions. The contribution of the free holes to the total rotation is extracted for each material and combined with Hall effect data. These combined data are used to deduce the light and heavy hole masses in GaAs and GaSb. For GaAs the masses are found to be 0 089m0, 0 51m0 and for GaSb they are found to be 0 056m0, 0 33m0. In Ge and Si, where the masses are already known from cyclotron resonance experiments, the data are used to find the relative populations of the light and heavy hole states, giving 5 8% and about 7% respectively. The observed frequency dependences of the rotation due to intervalence band transitions in GaAs and Ge are compared with those deduced theoretically by summing the effects of the direct Landau transitions.