# Phonon dispersion, Raman spectra and evidence for spin-phonon coupling in MnV$_2$O$_4$ from first-principles

## TL;DR

This study uses first-principles calculations to analyze phonon spectra and spin-phonon coupling in MnV₂O₄, explaining Raman spectral anomalies linked to coupled spin and orbital orderings at low temperatures.

## Contribution

It provides a theoretical analysis of spin-phonon interactions in MnV₂O₄, revealing the mechanism behind observed Raman anomalies through first-principles calculations and Landau-like theory.

## Key findings

- Identification of spin-phonon coupling effects on phonon spectra
- Explanation of Raman spectral anomalies at low temperature
- Mechanistic insight into coupled spin and orbital orderings

## Abstract

MnV$_2$O$_4$ in the spinel structure is known to exhibit coupled orbital and spin ordering, and its Raman spectra show interesting anomalies in its low-temperature phase. With a goal to explain this behavior involving coupled spins and phonons, we determine here the spin-phonon couplings in MnV$_2$O$_4$ 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 low-temperature phase.