Infrared Cyclotron Resonance in InSb

Far-infrared cyclotron resonance absorption in $n$-type InSb has been measured to determine the variation of the conduction electron effective mass with magnetic field. At high magnetic fields the absorption was resolved into a strong line with a weaker satellite line at lower photon energy and a broad, weak absorption at still lower energy. The interpretation of this structure in terms of the conduction-band properties of InSb is discussed.