Comparative study of tight-binding and ab initio electronic structure calculations focused on magnetic anisotropy in ordered CoPt alloy

TL;DR

This study compares tight-binding and ab initio calculations of magnetic anisotropy in CoPt alloy, refining parameters for better agreement and enabling future magnetotransport studies.

Contribution

It introduces a refined tight-binding model for CoPt that closely matches ab initio results, enhancing computational efficiency for magnetic property analysis.

Findings

Refined TB parameters improve agreement with ab initio data.

MAE calculations match experimental values at natural band filling.

The approach facilitates future studies of relativistic magnetotransport.

Abstract

An empirical multiorbital (spd) tight binding (TB) model including magnetism and spin-orbit coupling is applied to calculations of magnetic anisotropy energy (MAE) in CoPt L1_0 structure. A realistic Slater-Koster parametrisation for single-element transition metals is adapted for the ordered binary alloy. Spin magnetic moment and density of states are calculated using a full-potential linearized augmented plane-wave (LAPW) ab initio method and our TB code with different variants of the interatomic parameters. Detailed mutual comparison of this data allows for determination of a subset of the compound TB parameters tuning of which improves the agreement of the TB and LAPW results. MAE calculated as a function of band filling using the refined parameters is in broad agreement with ab initio data for all valence states and in quantitative agreement with ab initio and experimental data for the natural band filling. Our work provides a practical basis for further studies of relativistic magnetotransport anisotropies by means of local Green's function formalism which is directly compatible with our TB approach.