Hexagonal Zr3X (X = Al, Ga, In) Metals: High Dynamic Stability, Nodal Loop, and Perfect Nodal Surface States

Abstract

In recent years, topological semimetals/metals, including nodal point, nodal line, and nodal surface semimetals/metals, have been studied extensively because of their potential applications in spintronics and quantum computers. In this study, we predict a family of materials, Zr 3 X (X = Al, Ga, In), hosting the nodal loop and nodal surface states in the absence of spin-orbit coupling. Remarkably, the energy variation of the nodal loop and nodal surface states in Zr 3 X are very small, and these topological signatures lie very close to the Fermi level. When the effect of spin-orbit coupling is considered, the nodal loop and nodal surface states exhibit small energy gaps (<25 and 35 meV, respectively) that are suitable observables that reflect the spin-orbit coupling response of these topological signatures and can be detected in experiments. Moreover, these compounds are dynamically stable, and they consequently form potential material platforms to study nodal loop and nodal surface semimetals.

Electronic structure and physical properties of EuAuAs single crystal

“…It can be seen that the band-crossings appear along A-a, A-b, A-c and A-d paths, which infers that an A-centered nodal line should occur in the k z = 0.5 plane. These crossings exhibit a very little variation in energy along the selected paths, which is responsible for the flatness of the nodal line as discussed in other compounds [54]. We conclude that these band-crossings can be classified as type-I in the k z = 0.5 plane.…”