Influence of magnetic order on phonon spectra of multiferroic orthorhombic YMnO3

• Ab-initio lattice dynamics of orthorhombic YMnO3 is investigated.
• The phonon spectra obtained are sensitive to magnetic order in the system.
• The experimentally observed high-frequency peak is theoretically reproduced.
• The influence of on-site Coulomb parameter on the phonon spectra is demonstrated.

We perform a first-principles study of lattice dynamics in the low-temperature P21nmP21nm phase of orthorhombic YMnO3. By considering several possible antiferromagnetic types, we show how magnetic ordering of the system affects its vibrational properties. We find that the experimentally observed magnetic E-type corresponds to the most energetically favorable state and yields phonon spectra, which are consistent with experimental observations. The influence of on-site Coulomb correlations on phonon spectra is also examined. Such effects produce noticeable changes in the spectra and provide a step toward a more accurate description of lattice dynamics in YMnO3.