FINE INTERACTIONS AND THE JAHN-TELLER EFFECT IN LUMINESCENCE OF FE~2+ IN II-VI COMPOUNDS

摘要

Infrared luminescence spectra of Fe~(2+) in Ⅱ-Ⅵ zinc-blende structures show more than 4 unequally spaced lines. To explain such experimental features, we introduce a Jahn-Teller coupling to acoustical phonons of E symmetry. We apply and compare two independent methods: Born-Oppenheimer's and Lanczos'. Additionally we investigate the role of higher-order corrections such as spin-spin and third-order spin-orbit contributions to accurate calculation of energy levels. Details of the emission spectra of ZnS: Fe~(2+), ZnSe: Fe~(2+), ZnTe: Fe~(2+), and CdTe: Fe~(2+) are explained as due to a weak Jahn-Teller coupling which is enhanced when the energy of the coupling phonon is close to the spacing between electronic levels of appropriate symmetry.