Tetragonal CuMnAs alloy: role of defects

TL;DR

This study investigates the role of various defects in tetragonal CuMnAs alloy, combining ab initio calculations, resistivity measurements, and Monte Carlo simulations to understand their impact on material properties relevant for antiferromagnetic spintronics.

Contribution

The paper identifies the most probable defects in CuMnAs and quantifies their effects on resistivity and magnetic ordering, providing new insights into defect roles in this antiferromagnetic material.

Findings

Vacancies on Mn and Cu sublattices are most probable defects.

Resistivities of defected samples match experimental data.

Calculated Néel temperatures agree with experimental values.

Abstract

The antiferromagnetic (AFM) CuMnAs alloy with tetragonal structure is a promising material for the AFM spintronics. The resistivity measurements indicate the presence of defects about whose types and concentrations is more speculated as known. We confirmed vacancies on Mn or Cu sublattices and Mn$_{\rm Cu}$ and Cu$_{\rm Mn}$ antisites as most probable defects in CuMnAs by our new ab initio total energy calculations. We have estimated resistivities of possible defect types as well as resistivities of samples for which the X-ray structural analysis is available. In the latter case we have found that samples with Cu- and Mn-vacancies with low formation energies have also resistivities which agree well with the experiment. Finally, we have also calculated exchange interactions and estimated the N\'eel temperatures by using the Monte Carlo approach. A good agreement with experiment was obtained.