Time-dependent model for diluted magnetic semiconductors including band structure and confinement effects

A free-parameter theoretical model is developed in order to study the ultrafast dynamics in confined diluted magnetic semiconductors induced by laser. The hole-spin relaxation process is due to the Elliot-Yafet mechanism, which involves the scattering of the holes on the localized magnetic impurities. The role played by the quantum confinement and the band structure is analyzed. It is shown that the sample thickness and the background hole density strongly influences the phenomenon of demagnetization. Quantitative results are given for III-V ferromagnetic GaMnAs quantum wells of thickness 4 and 6 nm.