Strong linear polarization induced by a longitudinal magnetic field in II-VI semimagnetic semiconductor layers

Abstract

$(\mathrm{Cd},\mathrm{Mn})\mathrm{Te}$-based semimagnetic epilayers are studied by polarized reflection spectroscopy under a longitudinal magnetic field. We observe a huge linear polarization induced by the magnetic field: the degree of linear polarization reaches almost 100% when the heavy hole and light hole bands are brought to a resonance, driven by the giant Zeeman effect. A clear anticrossing between light and heavy hole exciton lines is also observed at the resonance. These features are characteristic of a light-heavy hole mixing by an anisotropic potential with ${C}_{2\mathrm{v}}$ symmetry. We suggest that the latter is due to in-plane uniaxial strain associated with anisotropic relaxation of the lattice mismatch.