First-principles study of the spin-lattice coulpling in spin frustrated DyMn$_2$O$_5$

TL;DR

This study uses density-functional theory to analyze the lattice dynamics and strong spin-phonon coupling in DyMn$_2$O$_5$, revealing significant phonon frequency changes with different spin configurations and their relation to magnetic phase transitions.

Contribution

First-principles calculations demonstrate the strong spin-phonon coupling and its impact on phonon modes in DyMn$_2$O$_5$, linking spin order to lattice dynamics.

Findings

Phonon frequencies match experimental data.

Spin configurations significantly alter phonon modes.

Short-range spin order affects Raman and IR phonons.

Abstract

The lattice dynamic properties and spin-phonon coupling in DyMn$_2$O$_5$ are studied by using the density-functional theory. The calculated phonon frequencies are in very good agreement with experiments. We then compare the phonon modes calculated from different spin configurations. The results show that the phonon frequencies change substantially in different spin configurations, suggesting that the spin-phonon coupling in this material is very strong. Especially, the short range spin ordering has drastic effects on the highest Raman and IR phonon modes that might be responsible for the observed phonon anomalies near and above the magnetic phase transitions.