Raman electron paramagnetic resonance in Zn1-xCoxTe and Cd1-xCoxTe

초록

Electronic Raman transitions due to the spin flip of the 3d electrons of Co2+ in Zn1-xCoxTe and Cd1-xCoxTe (x≤0.01) are observed at ℏωPM=g(Co2+)μBH with g(Co2+)=2.295±0.010 and 2.310±0.002, respectively. The intensity of Raman electron paramagnetic resonance (Raman-EPR) shows strong resonant enhancement when the incident or scattered photon energy coincides with that of a Zeeman component of the free exciton. Under resonant conditions, the Raman spectra display ZnTe-like (or CdTe-like) and CoTe-like longitudinal optical (LO) phonons in combination with the spin-flip transitions, a consequence of the Fröhlich interaction. In Zn1-xCoxTe, even the ZnTe-like TO phonon exhibited EPR sidebands but mediated by the deformation potential; the large p-d spin-spin exchange interaction in Co2+-based II-VI diluted magnetic semiconductors is the underlying microscopic mechanism.