First-principles modeling of multferroic RMn$_2$O$_5$

TL;DR

This study uses first-principles modeling to accurately reproduce and analyze the complex magnetic and ferroelectric phase transitions in RMn$_2$O$_5$, providing insights into their microscopic mechanisms.

Contribution

It introduces a first-principles effective-Hamiltonian approach to model the phase diagrams of RMn$_2$O$_5$, capturing key features of magnetic and ferroelectric transitions.

Findings

Polarization vs. temperature matches experimental data

Dielectric-constant step at phase transition is reproduced

Microscopic mechanisms of phase transitions are discussed

Abstract

We investigate the phase diagrams of RMn$_2$O$_5$ via a first-principles effective-Hamiltonian method. We are able to reproduce the most important features of the complicated magnetic and ferroelectric phase transitions. The calculated polarization as a function of temperature agrees very well with experiments. The dielectric-constant step at the commensurate-to -incommensurate magnetic phase transition is well reproduced. The microscopic mechanisms for the phase transitions are discussed.