Simulation of thermodynamic properties of magnetic transition metals from an efficient tight-binding model

TL;DR

This paper introduces an efficient tight-binding model within the Stoner approximation for simulating the thermodynamic properties of magnetic transition metals, enabling accurate atomistic simulations at finite temperatures.

Contribution

The paper presents a transferable tight-binding potential that incorporates magnetic variables for transition metals, validated across different magnetic states.

Findings

Successfully modeled the Curie temperature of cobalt.

Demonstrated the importance of atomic relaxations.

Generalized the model to various transition metals.

Abstract

Atomic scale simulations at finite temperature are an ideal approach to study the thermodynamic properties of magnetic transition metals. However, the development of interatomic potentials explicitly taking into account magnetic variables is a delicate task. In this context, we present a tight-binding model for magnetic transition metals in the Stoner approximation. This potential is integrated into a Monte Carlo structural relaxations code where trials of atomic displacements as well as fluctuations of local magnetic moments are performed to determine the thermodynamic equilibrium state of the considered systems. As an example, the Curie temperature of cobalt is investigated while showing the important role of atomic relaxations. Furthermore, our model is generalized to other transition metals highlighting a local magnetic moment distribution that varies with the gradual filling of the d states. Consequently, the successful validation of the potential for different magnetic configurations indicates its great transferability makes it a good choice for atomistic simulations sampling a large configuration space.