Optical detection of magnetic resonance of the zinc vacancy in ZnSe via magnetic circular dichroism

We report a study of the isolated zinc vacancy (${\mathit{V}}_{\mathrm{Zn}}$) in ZnSe using optical detection of magnetic resonance (ODMR) via magnetic circular dichroism (MCD) in absorption. Three MCD bands associated with ${\mathit{V}}_{\mathrm{Zn}}^{\mathrm{-}}$ are observed at 1.0, 1.4, and 2.65 eV. The 1.4- and 2.65-eV bands have previously been observed by stress-induced linear dichroism studies. Detection of the band at 1.0 eV provides important confirmation of a previously proposed molecular orbital model for the defect. The MCD-ODMR signals are absorptionlike and disappear for the applied magnetic field along the defect axis. This unusual behavior is explained by calculating the dipole transition probabilities of the MCD transitions using this model, but expanded to include spin-orbit interaction.