Spin-Flip Raman Scattering Study of Deep Acceptor States in Zinc-Telluride and of the Semimagnetic Semiconductors Zinc-Manganese - Selenide and Cadmium-Manganese - Sulfide.
We have used the technique of spin-flip Raman scattering to investigate ZnTe:Cu, Ag, Au and the semimagnetic semiconductors Zn(,1-x)Mn(,x)Se and Cd(,1-x)Mn(,x)S. The observed scattering mechanisms in ZnTe:Cu, Ag, Au include spin-flip of free heavy holes, of holes bound to acceptors and donors, and of photoexcited electrons. The measured g-values are discussed in terms of trends in acceptor g -values. In Zn(,1-x)Mn(,x)Se and Cd(,1-x)Mn(,x)S we observe conventional (linear) spin-flip thought to be due to electrons localized at Mn sites. We also observe exchange-induced spin-flip attributed either to conduction electrons or to electrons bound to neutral shallow donors. This type of scattering has a Brillouin rather than a linear dependence on applied magnetic field and results from an s-d exchange interaction between band electrons and electrons localized at Mn sites. The fitted Brillouin form reflects an antiferromagnetic ordering of the Mn local moments, revealed by an effective temperature which is greater than the ambient temperature and which increases with an increase in Mn concentration. It is suggested that the antiferromagnetic ordering arises from an indirect exchange, the Bloembergen-Rowland mechanism, involving virtual interband transitions between valence and conduction bands.
- Pub Date:
- Physics: Condensed Matter