# First-principle study of the melting temperature of MgO

## TL;DR

This study uses first-principles calculations, including the RPA method, to accurately predict the melting temperature of MgO, comparing different density functionals and providing high-precision results.

## Contribution

It introduces a high-accuracy first-principles approach using RPA for calculating the melting point of MgO, surpassing previous methods in precision.

## Key findings

- RPA predicts MgO melting temperature as 3043±86 K.
- PBE functional estimates melting at 2747±59 K.
- SCAN functional estimates melting at 3032±53 K.

## Abstract

Using first-principles only, we calculate the melting point of MgO, also called periclase or magnesia. The random phase approximation (RPA) is used to include the exact exchange as well as local and non-local many-body correlation terms, in order to provide high accuracy. Using the free energy method, we obtain the melting temperature directly from the internal energies calculated with DFT. The free energy differences between the ensembles generated by the molecular dynamics simulations are calulated with thermodynamic integration or thermodynamic perturbation theory. The predicted melting temperature is $T_m^\text{RPA} =3043\pm 86$ K, and the values obtained with the PBE and SCAN functionals are $T_m^\text{PBE} = 2747 \pm 59$ K and $T_m^\text{SCAN} = 3032\pm 53 $ K.