Spontaneous Magnetization in Diluted Magnetic Semiconductor Quantum Wells

A diluted magnetic semiconductor (DMS) quantum well is an interesting system for explor-ing spintronic applications. We calculated the spontaneous magnetization (SM) in a 100-Å Ga1−xMnxAs/Al0.35Ga0.65As quantum well. The Schrodinger equation was described by a 4×4 Luttinger Hamiltonian in the envelope function approximation with the exchange interaction be-tween Mn ions and holes treated in the mean-field approximation. The Schrodinger-Poisson-DMS self-consistency was solved by using the finite element method. We studied how the SM depended on the hole concentration p, the temperature T, the effective Mn concentration xeff, the antiferro-magnetic temperature TAF, and the exchange integral βNo. For T = 0 K, xeff = 0.05, TAF = 0.5 K, and βNo = − 1.2 eV, the SM begins to appear at p = 5 × 1017 cm−3 and saturates around 3 × 1019 cm−3. For p = 1018 cm−3, the SM disappears around 5 K