Raman study of a magnetic phase transition in the MnPS3 single crystal

Abstract

The Raman scattering spectra for the MnPS3 single crystal have been studied at frequencies ranging from 5 to 1200 cm−1, for temperatures ranging from 5 to 295 K. This is the first time that studies of low-temperature polarized Raman spectra in a magnetically ordered phase are presented for MnPS3. Energy splitting between some of Ag- and Bg-modes, which were previously believed to be energy equivalent in crystals from this family, has been found. The nature of the additional phonon lines observed in the Raman scattering spectra is discussed. It is found that at low temperatures, the magnetic scattering spectrum has a complex form that is related to the presence of both two-magnon and a phonon-magnon bands. The vibrational properties of the MnPS3 crystal were calculated using the LDA approximation with the DFT-D (OBS) dispersion correction implemented in the CASTEP computation package. Phonon dispersion curves and the total and partial phonon densities of states have been calculated in the antiferromagnetic phase of the MnPS3 crystal. The calculated results are in good agreement with the experimental Raman spectra.