Orbital ordering in MnV2O4 from ab-initio phonon and Raman scattering study

Abstract

Using ab-initio phonon calculations within density functional theory framework, we have studied the phonon density of states, and obtained the nature of orbital ordering in the low temperature structure of MnV2O4 from the analysis of corresponding Raman spectrum. In this system V3+ ions are orbitally active and the d-d excitations between neighbouring V ions contribute to the Raman spectrum. A detailed analysis of Raman spectra established the nature of orbital ordering at V sites to be A-type antiferro-orbital ordering, where one 3d electron occupies dxy orbital at every V site and another electron occupies either dxz or dyz orbital alternatively along c axis. Stability and the orbital ordering of this compound are found to be correlation driven. © 2017 Author(s).