The role of electronic correlations on the phonon modes of MnO and NiO

TL;DR

This study investigates how magnetic order affects phonon behavior in MnO and NiO, revealing significant anisotropy and non-cubic dynamic properties through neutron scattering experiments.

Contribution

It provides new insights into the influence of magnetic order on phonon modes in MnO and NiO, challenging the assumption of cubic symmetry in their dynamic properties.

Findings

Phonon spectra split by about 10% below Tn

Magnetic order induces phonon anisotropy

Dynamic properties are substantially non-cubic

Abstract

The possibility of magnetic-order induced phonon anisotropy in single crystals of MnO and NiO is investigated using inelastic neutron scattering. Below Tn both compounds exhibit a splitting in their transverse optical phonon spectra of approximately 10%. This behavior illustrates that, contrary to general assumption, the dynamic properties of MnO and NiO are substantially non-cubic.