Spin Exchange in Excitons, the Quasicubic Model and Deformation Potentials in II-VI Compounds

Spatially resolved photoluminescence mapping of single CdS nanosheets

“…Recent Raman measurements 22 also indicate the presence of significant stress in the nanosheets. A spatial gradient of stress from the center to the edge of the nanosheet would affect the A and B excitons differentially, 23 resulting in potential minima either along the edge or in the center for the A-and B-valence band excitons, respectively. More detailed measurements with the higher spatial resolution offered by use of a solid immersion lense are clearly required to interpret these results.…”

Negative spin-exchange splitting in the exciton fine structure of AlN

“…ZnO has a large E X of around 60 meV and a large j ¼ 5:6 meV. 4 Alas, in this case, the valence band spacing from the highest valence band to the next one is 4.5 meV only, much lower than the undisturbed distance between the excitons split by spin-exchange interaction of 2j ¼ 11:2 meV. This means that the intermixing between the excitons formed from holes of the different valence bands makes any investigation complicated in ZnO.…”

Spin splitting of donor-bound excitons in ZnO due to combined stress and spin exchange

“…5 They found that the combined effects of stress and the electronhole exchange interaction in a quasicubic model were able to predict the splitting and polarization pattern of the free exciton. These studies were extended to several other materials by Langer et al 6 The stress effects on excitons bound to shallow acceptors in zinc-blende materials were later investigated. 7,8 This is a report of spin splitting due to stress in donor-bound excitons.…”

“…3 can be explained by using the theory outlined in Ref. 6. If one takes the electron spin of the donor-bound electron being aligned or antialigned to that of the charge cloud of the donor, there is a strain matrix element which splits into two states.…”