SPIN-FLIP RAMAN-SCATTERING STUDIES OF ZNSE ZN1-XMNXSE MULTIPLE-QUANTUM-WELL STRUCTURES/

Studies of electron spin-flip Raman scattering in a series of ZnSe/Zn1 -xMnxSe heterostructures of different quantum well widths are reported , In all the specimens studied, a single spin-flip Raman band was obse rved with a Raman shift which showed the expected modified Brillouin f unction dependence on magnetic field and temperature. The dependence o f the scattering intensity on the excitation energy shows strong reson ant enhancement at energies corresponding to the quantum well exciton transitions, which, together with the selection rules, indicates that the spin-flip Raman signals arise from electrons localised in the ZnSe quantum wells, In our previous studies, the magnitude of the spin-fli p Raman shift has been interpreted as a measure of the penetration of the electron envelope wavefunction into the barrier, leading to a simp le means of determining the conduction band offset (including any cont ribution due to strain) of the system. However, in the present case, w here the manganese concentration of the barrier is large and where the band offset is expected to be small, simple interpretation of the dat a in this way is not possible. Two effects in particular complicate th e analysis of the data: the roughness of the heterointerface and the m odified probability, compared to bulk material, of manganese antiferro magnetic spin-pairing at that interface. We use the results of recent theoretical work to show that the spin-flip Raman spectra are very sen sitive to the state of the interface.