Spin-assisted photoluminescence of polycrystalline α-MnSe

We have studied photoluminescence of α-MnSe in the antiferromagnetic and paramagnetic phases. Two broad, possibly multi-component emission bands centred at about 1.53 and 1.66 eV are observed at 20 K. The frequencies and intensities of these bands show step-like shift in the vicinity of TN. On the basis of difference in peak energies at T=1.8 K and TN the d-p-d superexchange interaction in excited state is estimated to be J2g(exc)=0.918 meV.