Role of Exciton Dispersion and Exciton-Magnon Interactions on the Shape of Magnon Sidebands in Stressed MnF2
- 1 February 1968
- journal article
- research article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 39 (2) , 1145
- https://doi.org/10.1063/1.1656203
Abstract
We have previously1 studied the effect of stress on 4T1 excitons E1 and E2 in the optical absorption spectra of MnF2 and magnon side bands of them. The effect of stress on the zone‐center excitons (k=0) was understood as well as some features of the magnon side bands. However the shape of the side bands, the peak positions and the relative intensities remained unexplained within a single exciton theory, as well as changes in the side bands with stress. This disagreement may be due to exciton dispersion or exciton‐magnon interaction since in absorption an exciton and a magnon are created simultaneously and they may interact. However a magnon side band in the emission spectra corresponds to the simultaneous creation of a magnon and annihilation of an exciton and they do not interact: any anomaly in this case will be due to exciton dispersion. We have analyzed both, emission and absorption spectra under (100) stress, and the conclusion is that the main effect is the exciton‐magnon interaction. Any exciton dispersion must be smaller than 1 cm−1. Using a simple model for exciton magnon interaction we are able to explain the observed σ side bands in the absorption spectra. The main contribution derives from interaction between second neighbors in second‐order perturbation.This publication has 1 reference indexed in Scilit:
- Effect of Uniaxial Stress on Magnon Sidebands in MnPhysical Review Letters, 1966