ELECTRONIC SPINS AND LOCALIZED MAGNETIC MOMENTS IN DILUTE MAGNETIC SEMICONDUCTOR QUANTUM WELLS

摘要

Electrical transport measurements are reported on 2-DEG in a CdMnTe quantum well structure. At low magnetic fields the Shubnikov-de Haas oscillations show a beating pattern with nodes which are a direct consequence of the large Pauli paramagnetism. The effective electron Zeeman splitting (E_Z) has been tuned via the s-d exchange interaction in order to probe the quantum Hall effect under conditions of vanishing Zeeman energy. We have observed that reducing E_Z to zero does not necessary imply a closing of the spin gap.