Raman study of magnetic phase transition in the MnPS3 single crystal

Abstract

The Raman spectra of the MnPS₃ single crystal were investigated in the frequency region of 5–1200 см^–1 in the 5–295 K temperature range. For the first time, the studies of low-temperature polarized Raman spectra in a magnetically ordered phase are presented. The energy splitting between some of the A_g- and B_g-modes which were previously considered as the energy equivalent in crystals of this family was found. The nature of additional phonon lines observed in Raman spectra is discussed. It was found that at low temperatures magnetic scattering spectrum has a complex form which is associated with the presence of both a two-magnon and phonon-magnon bands. The vibrational properties of the MnPS₃ crystal were calculated using the LDA approximation with DFT-D (OBS) dispersion correction implemented in the CASTEP package. The calculation of phonon dispersion curves and total as well as partial densities of phonon states was carried out in the antiferromagnetic phase of the MnPS₃ crystal. The obtained results of the performed calculation are in good agreement with measured experimental Raman spectra.