Studies of the optical band positions, spin-Hamiltonian parameters and defect structure for Cr3+ in CdIn2S4 crystal

Abstract

The calculations of optical band positions and spin-Hamiltonian parameters (g factors g//, g⊥ and zero-field splitting D) for Cr3+ ion at the trigonal octahedral In3+ site in semiconducting spinel CdIn2S4 have been carried out by using the complete diagonalization (of energy matrix) method based on the two-spin–orbit-parameter model. In the model, differing from the conversional one-spin–orbit-parameter in the widely-used crystal-field theory, both the contribution to spin-Hamiltonian parameters from the spin–orbit parameter of central dn ion and that of ligand are contained. The calculated results are in reasonable agreement with the experimental values. It is found from the calculations that the MO6 octahedral cluster in CdIn2S4:Cr3+ changes from the trigonal elongation in the host crystal to the trigonal compression in the Cr3+ impurity center owing to the impurity-induced local lattice relaxation. The results are discussed.