Ab-initio study of the RbEuFe₄As₄ superconductor

ABSTRACT

The results of ab-initio calculations of the electronic structure and magnetism of the new superconductor RbEuFe${}_4$As${}_4$ are reported. The electronic band structure and the density of states are presented and discussed in detail. The electric charge density distributions along different crystallographic planes are presented, and the origin of the chemical bonding between the constituent atoms is discussed in detail. The evidence is provided for the existence of a mixture of ionic, covalent, and metallic bonding. It is demonstrated that the magnetic moment is mainly due to the strongly localised Eu $4f$ states. An almost negligible magnetic moment carried by the Fe atoms is shown to be due to the symmetry of the Fe spin-up and spin-down states. It is demonstrated that the electrical and chemical properties of RbEuFe${}_4$As${}_4$ are closely linked with the presence of the Fe $3d$ states in the Fermi energy region. The Fermi surfaces show the presence of hole-like and electron-like pockets, respectively, at the center and corners of the Brillouin zone. The results of the calculations of the elastic properties and the ${}^{57}$Fe and ${}^{151}$Eu hyperfine-interaction parameters are also presented.

KEYWORDS:

• Density of states
• energy band structure
• magnetic moment
• hyperfine interactions

Disclosure statement

No potential conflict of interest was reported by the authors.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC).