BOUND MAGNETIC EXCITON POLARON ACCOMPANIED BY LARGE LATTICE DISPLACEMENT AND LUMINESCENCE IN EUSE

We have studied the luminescence in EuSe using the photoinduced locali zed magnetic polaron (PILMP) model previously proposed for EuTe (Phys. Rev. B 52 (1995) 8140). This paper shows the characteristics of the l uminescence around 1.47 eV recently reported (J. Phys. Sec. Japan 63 ( 1994) 4616)for EuSe is consistent with this model. The PILMP is bound to the localized 4f hole that is created in the photoabsorption proces s, and accompanies a large lattice displacement induced by the 4f hole . By taking into account this large lattice displacement, we can under stand the characteristics of the luminescence, such as the emission en ergy, the Stokes shift and the spectrum width, quantitatively. The exi stence of the large lattice displacement is a common feature for EuTe and EuSe. On the other hand, the magnetic polaron effect in EuSe is qu ite large in comparison to that in EuTe, which causes the difference i n the temperature dependence of the emission energy and the spectrum w idth between EuTe and EuSe. Through the analysis of the luminescence i n EuSe, we can see a typical magnetic polaron bound to the 4f hole, th at is a bound magnetic exciton polaron accompanied by the large lattic e displacement. (C) 1998 Elsevier Science B.V. All rights reserved.