Dynamical Jahn-Teller Interaction in Optical and paramagnetic Resonance Spectra –Application to a Cu Deep Impurity in II-VI Semiconductors–

Abstract

A theoretical treatment for vibronic levels of an interacting electron and vibration system is developed so as to calculate g -values in paramagnetic resonance and vibronic structures in optical spectra simultaneously, under the assumption that the electrons interact with localized vibrations. The variations of the g -values and absorption and emission spectra with the interaction strength are shown for weak and intermediate interactions, choosing Cu 2+ ions in II-VI semiconductors as an object of study. Two important effects of the Jahn-Teller interaction are clarified. First, the observed g -values which differ markedly for different semiconductors are due to the dynamical Jahn-Teller interaction. Second, the vibronic spectra change drastically at the interaction strength at which two vibronic levels cross each other, reflecting the breakdown of the adiabatic approximation. Finally the absorption and emission spectra of Cu 2+ ions in ZnO, CdS and ZnS are calculated with appropriate parameters and compared with experiments.