A study was made of anharmonic and local order effects in the Raman spectrum of the ordered vacancy semiconductors ZnGa2Se4 and MnGa2Se4. In MnGa2Se4 the asymmetry of the Se-vacancy breathing like mode and its temperature dependence were satisfactorily explained by a model based on the anharmonic coupling of the phonon with second order phonon excitations. In ZnGa2Se4, however, asymmetry was not fully accounted for with this model. The discrepancy was attributed to short-range order effects in the, on the average, cation disordered structure of ZnGa2Se4. These effects were taken into account by means of the spatial correlation model.

Anharmonic Interactions in the Raman Spectrum of ZnGa2Se4 and MnGa2Se4 Ordered Vacancy Compounds. P.Alonso-Gutiérrez, M.L.Sanjuán: Journal of Physics - Conference Series, 2007, 92[1], 012150 (4pp)