Melting curve of face-centred-cubic nickel from first principles calculations

TL;DR

This study calculates the melting curve of face-centered cubic nickel up to 100 GPa using first principles DFT methods, providing insights into melting temperatures and slopes with some discrepancies at high pressures.

Contribution

It introduces two complementary first principles approaches for calculating the melting curve of nickel under high pressure.

Findings

Zero pressure melting temperature is slightly underestimated at 1637 K.

High-pressure melting temperatures are higher than recent experimental measurements.

The zero pressure melting slope is 30 ± 2 K, aligning well with experimental data.

Abstract

The melting curve of Ni up to 100 GPa has been calculated using first principles methods based on density functional theory (DFT). We used two complementary approaches: i) coexistence simulations with a reference system and then free energy corrections between DFT and the reference system, and ii) direct DFT coexistence using simulation cells including 1000 atoms. The calculated zero pressure melting temperature is slightly underestimated at $1637 \pm 10$ K (experimental value is 1728 K), and at high pressure is significantly higher than recent measurements in diamond anvil cell experiments [Phys. Rev. B {\bf 87}, 054108 (2013)]. The zero pressure DFT melting slope is calculated to be $30 \pm 2$ K, in good agreement with the experimental value of 28 K.