Efficient calculation of magnetocrystalline anisotropy energy using symmetry-adapted Wannier functions

TL;DR

This paper introduces a symmetry-adapted Wannier function approach for efficient calculation of magnetocrystalline anisotropy energy, reducing computational cost while maintaining accuracy for magnetic materials.

Contribution

The authors develop a Wannier orbital tight-binding model that incorporates crystal and spin symmetries, enabling faster magnetocrystalline anisotropy calculations.

Findings

Model accurately predicts anisotropy energy around 10 μeV/f.u.

Method reduces computational effort for k-point convergence.

Validated on FePt and FeNi materials.

Abstract

Magnetocrystalline anisotropy, a crucial factor in magnetic properties and applications like magnetoresistive random-access memory, often requires extensive $k$-point mesh in first-principles calculations. In this study, we develop a Wannier orbital tight-binding model incorporating crystal and spin symmetries and utilize time-reversal symmetry to divide magnetization components. This model enables efficient computation of magnetocrystalline anisotropy. Applying this method to $\mathrm{L1_0}$ $\mathrm{FePt}$ and $\mathrm{FeNi}$, we calculate the dependence of the anisotropic energy on $k$-point mesh size, chemical potential, spin-orbit interaction, and magnetization direction. The results validate the practicality of the models to the energy order of $10~[\mathrm{\mu eV}/f.u.]$.