Ground state splitting of 8S rare earth ions in semiconductors -: art. no. 094429

We propose a mechanism leading to ground state splitting for rare earth S-8 ions in semiconductor crystals. The resulting splitting is due to three effects; the first is the intra-atomic 4f-5d spin-spin interaction, the second one is the spin-orbit interaction for 5d electrons, and the third one is their hybridization with the valence band states of the semiconductor host. The resulting splitting depends significantly on the position of the 5d level with respect to the semiconductor host band structure. We also discuss a different model, already known in the literature, which is also based on the ion-band state hybridization. For both models, as an example, we present results of numerical calculations for rare earth ions in the IV-VI semiconductor PbTe.