Generalized Glauber states for the Jahn-Teller coupling of Fe2+ in ZnTe and ZnS

A method based on generalized Glauber states is developed to deal with the Jahn-Teller effect on magnetic impurities in II-VI semiconductors, and is successfully applied to ZnTe:Fe2+. The method is also applied to ZnS:Fe2+ which reaches stability for a lower number of vibrational quanta N, in order to have a basis for comparison with another method. It is found that the present method is more powerful than a previous one based on Born-Oppenheimer functions. The low-energy vibronic functions remain as stable solutions for all values of the coupling parameter. In the case of ZnTe:Fe2+, good agreement with both experimental results and previous theoretical calculations is obtained for a Jahn-Teller energy of 250 cm-1. In the case of ZnS:Fe2+ where no manifestation of vibronic coupling has been observed, an upper limit for this energy is found. Possible extensions of this work and their expected difficulties are also discussed.