12 July 2002 Excitonic-type polaron states: photoluminescence in SBN and in other ferroelectric oxides
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Proceedings Volume 4766, XI Feofilov Symposium on Spectroscopy of Crystals Activated by Rare-Earth and Transition Metal Ions; (2002) https://doi.org/10.1117/12.475343
Event: XI Feofilov Symposium on Spectroscopy of Crystals Activated by Rare-Earth and Transition Metal Ions, 2001, Kazan, Russian Federation
Abstract
A theoretical model for two characteristic photoluminescence (PL) bands in SBN, 'green luminescence' and 'red luminescence' is proposed on the basis of the extended photoluminescence experiments in SBN:Cr, and also in SBN:Ce and in nominally pure SBN systems under different conditions. While the RL-band is suggested to be connected with charge transfer vibronic exciton (CTVE) clusters induced by Cr3+ impurities in the Nb-sites, the GL- band is connected with Nb4+ electronic polarons in a new, charge transfer excited states. Here Nb4+ centers are the cores of the CTVE clusters induced by these charged scores. The PL mechanism is the in-cluster CTVE recombination for both bands under discussion. But the CTVE states are quasi-resonantly mixed here with 4T2 states of the Cr3+ core in the RL-band case, and with 5s-states of the Nb4+ core in the GL-band case. The role of excitonic polarons of CTVE nature is also discussed in connection with 'green' luminescence origin in KTaO3 and KNbO3 crystals.
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V. S. Vikhnin, V. S. Vikhnin, I Kislova, I Kislova, A B Kutsenko, A B Kutsenko, S E Kapphan, S E Kapphan, } "Excitonic-type polaron states: photoluminescence in SBN and in other ferroelectric oxides", Proc. SPIE 4766, XI Feofilov Symposium on Spectroscopy of Crystals Activated by Rare-Earth and Transition Metal Ions, (12 July 2002); doi: 10.1117/12.475343; https://doi.org/10.1117/12.475343
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