Interface Sensitive Study of Spin Injection, Transport and Relaxation in Ferromagnet-Semiconductor Quantum Well Systems for Spin Applications

摘要

In this report, we present our observation of optically excited nonequilibrium spin dynamics in (Ga,Mn)As at room temperature. Our observation demonstrates two different regimes: 1) an initial ultrafast oscillatory behavior during the subpicosecond and picosecond time scale after photo- excitation, which we find to be related to photo-induced carrier (electrons and holes) spins; 2) a slow demagnetization over hundreds of picoseconds, which, we believe, results from not only strong-coupled hole-Mn spins but also interactions between electron spins and Mn moments.