Electronic structure and physical properties of EuAuAs single crystal

TL;DR

This study investigates EuAuAs single crystals, revealing antiferromagnetic order below 6 K, metallic behavior, and topological features like nodal lines and Dirac points, suggesting it as a candidate for an antiferromagnetic topological nodal-line semimetal.

Contribution

The paper combines experimental measurements and electronic structure calculations to identify EuAuAs as a topologically nontrivial antiferromagnetic semimetal with nodal lines and Dirac points.

Findings

Antiferromagnetic order below 6 K.

Presence of nodal line and Dirac point in electronic structure.

EuAuAs is a candidate for an antiferromagnetic topological semimetal.

Abstract

High-quality single crystals of EuAuAs were studied by means of powder x-ray diffraction, magnetization, magnetic susceptibility, heat capacity, electrical resistivity and magnetoresistance measurements. The compound crystallizes with a hexagonal structure of the ZrSiBe type (space group $P6_3/mmc$). It orders antiferromagnetically below 6 K due to the magnetic moments of divalent Eu ions. The electrical resistivity exhibits metallic behavior down to 40 K, followed by a sharp increase at low temperatures. The magnetotransport isotherms show a distinct metamagnetic-like transition in concert with the magnetization data. The antiferromagnetic ground state in \mbox{EuAuAs} was corroborated in the \textit{ab initio} electronic band structure calculations. Most remarkably, the calculations revealed the presence of nodal line without spin-orbit coupling and Dirac point with inclusion of spin-orbit coupling. The \textit{Z}$_2$ invariants under the effective time reversal and inversion symmetries make this system nontrivial topological material. Our findings, combined with experimental analysis, makes EuAuAs a plausible candidate for an antiferromagnetic topological nodal-line semimetal.