Magnetic-Field-Induced Level Crossing and the Spin Dynamics of Excitons in Zn1− xMn xTe/ZnTe Quantum Wells.

Magnetic-field-induced level crossing and the spin dynamics of excitons in a Zn_{1− x}Mn _xTe/ZnTe single quantum well are studied. The circularly-polarized photoluminescence (PL) shows that the down spin branch of the Zn_{1− x}Mn _xTe exciton overlaps with both the up and down spin branches of the ZnTe exciton at a crossing field ( H_c) of 4 T, due to the giant Zeeman shift of Zn_{1− x}Mn _xTe. The PL intensities and lifetimes in each layer become gradually equal toward H_c, which shows the mixing of wavefunctions of the excitons generated in each layer. Above H_c, each branch of the spin-polarized exciton separates again. The lifetimes of the spin-polarized exciton PL reflect the spin-flip relaxation in ZnTe and the spin mixing between Zn_{1− x}Mn _xTe and ZnTe layers. [ABSTRACT FROM AUTHOR]