Phonon dispersion, Raman spectra, and evidence for spin-phonon coupling in MnV2 O4 from first principles

Abstract

MnV2O4 in the spinel structure is known to exhibit coupled orbital and spin ordering and its Raman spectra show interesting anomalies in its lowerature phase. With a goal to explain this behavior involving coupled spins and phonons, we determine here the spin-phonon couplings in MnV2O4 from a theoretical analysis of its phonon spectra and their dependence on spin ordering and electron correlations, obtained from first-principles density functional theoretical calculations. Using these in an analysis based on a Landau-like theory, we uncover the mechanism governing the Raman anomalies observed in its lowerature phase. © 2020 American Physical Society.