Abstract
Using density-functional theory, we investigate the electronic, magnetic, and hyperfine-interaction properties of the 112-type iron-pnictide compound {hbox {EuFeAs}}_2, which is isostructural to the high-temperature iron-based superconductor {hbox {Ca}}_{1-x}{hbox {La}}_x{hbox {FeAs}}_2. We show that the band structure of {hbox {EuFeAs}}_2 is similar to that of the 112-type compounds’ family, with hole-like and electron-like bands at the Brillouin-zone center and corners, respectively. We demonstrate that the bands near the Fermi level originate mainly from the Fe atoms. The presence of a mixture of ionic and covalent bonding is predicted from the charge-density and atom-resolved density-of-states calculations. There is good agreement between the calculated hyperfine-interaction parameters with those obtained from the ^{57}Fe and ^{151}Eu Mössbauer measurements. The spatial distribution of atoms in {hbox {EuFeAs}}_2 leads to an in-plane 2D magnetism. Moreover, ab-initio calculations predict the compound’s magnetic moment and the magnetic moments of each constituent atom. Also, the density of states profile provides insight into the relative magnitude of these moments. Electronic structure calculations and Fermi surface topology reveal various physical and chemical properties of {hbox {EuFeAs}}_2. Valence electron density maps indicate the co-existence of a wide range of chemical bonds in this system, and based on structural properties, the transport characteristics are deduced and discussed. A thorough analysis of the atomic structure of {hbox {EuFeAs}}_2 and its role in the bond formation is presented.
Highlights
Using density-functional theory, we investigate the electronic, magnetic, and hyperfine-interaction properties of the 112-type iron-pnictide compound EuFeAs2, which is isostructural to the hightemperature iron-based superconductor Ca1−x Lax FeAs2
We carried out first-principles calculations of the electronic structure and Mössbauer hyperfine-interaction parameters of EuFeAs2 in the context of density-functional theory employing the full-potential linearized augmented-plane-wave method that is implemented in the WIEN2k package[15]
The unit cell of EuFeAs2 is in the form of a cuboid (Fig. 1a), which is highly elongated along the a direction ( a ≫ b, c, Table 1)
Summary
Using density-functional theory, we investigate the electronic, magnetic, and hyperfine-interaction properties of the 112-type iron-pnictide compound EuFeAs2 , which is isostructural to the hightemperature iron-based superconductor Ca1−x Lax FeAs2. Electronic structure calculations and Fermi surface topology reveal various physical and chemical properties of EuFeAs2. Density-functional theory calculations on these class of iron-based pnictides were performed They suggest the existence of four hole-like and two electron-like bands intersecting the Fermi level ( EF ) around, respectively, the Ŵ and M points, which are related to the Fe 3d and As 4p orbitals[1]. This work’s main objective is to study the origin of some of the physical properties of EuFeAs2 via a detailed investigation of its electronic structure using the ab-initio density-functional theory calculations. With the aid of ab-initio calculations, one can compare the experimental results with those derived from computations
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