Direct determination of the zero-field splitting for a single Co2+ ion embedded in a CdTe/ZnTe quantum dot

Article

关键词: MAGNETIZATION-STEP;    AXIAL ANISOTROPY;    SPIN DYNAMICS;    CDSE;    SEMICONDUCTOR;    ZN1-XCOXO;    COBALT;   

DOI  :  10.1103/PhysRevB.97.045305

来源: SCIE

【 摘 要 】

When a Co2+ impurity is embedded in a semiconductor structure, crystal strain strongly influences the zero-field splitting between Co2+ states with spin projection S-z = +/- 3/2 and S-z = +/- 1/2. Experimental evidence of this effect has been given in previous studies; however, direct measurement of the strain-induced zero-field splitting has been inaccessible so far. Here this splitting is determined thanks to magneto-optical studies of an individual Co2+ ion in an epitaxial CdTe quantum dot in a ZnTe barrier. Using partially allowed optical transitions, we measure the strain-induced zero-field splitting of the Co2+ ion directly in the excitonic photoluminescence spectrum. Moreover, by observation of anticrossing of S-z = +3/2 and S-z = -1/2 Co2+ spin states in a magnetic field, we determine the axial and in-plane components of the crystal field acting on the Co2+. The proposed technique can be applied to optical determination of the zero-field splitting of other transition-metal ions in quantum dots.

【 授权许可】

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