The infra-red Faraday effect in n-type AlSb and GaP and in undoped GaP

Abstract

Infra-red Faraday rotation has been measured in n-type AlSb giving a value of the electron effective mass m* = 0.39±0.03 m₀. Experimental curves showing the rotation due to the subsidiary absorption bands at 4.3 and 3.0 μm in n-type AlSb and GaP, respectively, are given. These provide evidence for rejecting the postulate that a deep donor level causes this excess absorption. Measurements of interband Faraday rotation in GaP for wavelengths between 0.5 and 5.0 μm are compared with theoretical results. They show that the contribution of the fundamental indirect edge predominates, and give an effective g factor of +15 for this transition.