PIEZOMAGNETISM AND EXCITONS IN THE CDTE CD(MN)TE AND CD(MN)TE ZN(MN)TE QUANTUM-WELL SYSTEMS

In a semi-magnetic semiconductor (SMSC) such as Cd(Mn)Te, at high Mn concentrations (x > 0.40) antiferromagnetic (AF) Mn-Mn fluctuations, in the presence of the sp-d coupling between band carriers and the local (Mn) moments, give rise to a fluctuation-induced e-h interaction which can increase the exciton binding energy. In strained layer SMSC systems such as CdTe/Cd(Mn)Te and Cd(Mn)Te/Zn(Mn)Te, the lattice mismatch strain stabilizes a particular AF domain against spin flop in the presence of a magnetic field, with the AF order parameter aligned along the strain anisotropy axis. For x=0.60 in the CdTe/Cd(Mn)Te system, we find the critical magnetic field needed to destabilize the domain and cause spin flop (Hc ∼ 50 kG), and calculate the change in exciton binding energy due to AF fluctuations (with no mass renormalization), ΔE=3 meV. © 1990.