Spin effects in InSb quantum wells

Among the III–V semiconductors, InSb has the smallest electron effective mass and the largest g-factor. We make use of these properties to explore some aspects of electron spin in InSb quantum wells with far-infrared magneto-spectroscopy. We observe the clear signature of spin-resolved cyclotron resonance caused by the non-parabolicity of the conduction band. We observe avoided-level crossings at magnetic fields where Landau levels of the same spin are predicted to intersect. We also study electron spin resonance in the far infrared over a wide range of magnetic field. In samples with symmetrically designed quantum wells we find cyclotron masses and observed g-factors in good agreement with a Pidgeon–Brown analysis adapted to the two-dimensional band structure. However, the spin splitting approaches View the MathML source as the magnetic field approaches zero in samples intentionally asymmetrically doped.