Trends in structural and electronic properties for layered SrRu2As2, BaRu2As2, SrRh2As2 and BaRh2As2 from ab initio calculations

TL;DR

This study uses first-principles calculations to analyze how substituting different elements affects the structural and electronic properties of layered arsenides similar to ThCr2Si2, revealing anisotropic deformations and changes in electronic topology.

Contribution

It provides a systematic analysis of structural and electronic trends in SrRu2As2, BaRu2As2, SrRh2As2, and BaRh2As2 using ab initio methods, highlighting the impact of element substitution.

Findings

Substituting Sr with Ba causes anisotropic structural deformations.

Replacing Ru with Rh increases three-dimensionality of electronic dispersion.

The bonding is complex, combining metallic, ionic, and covalent interactions.

Abstract

Based on first-principle FLAPW-GGA calculations, we have investigated the systematic trends in structural and electronic properties of a newly discovered group of ThCr2Si2-like arsenides: SrRu2As2, BaRu2As2, SrRh2As2 and BaRh2As2. Our results show that the replacement of an alkaline earth metal (Sr - Ba) and 4d metal (Ru - Rh) leads to various types of anisotropic deformations of the crystal structure caused by strong anisotropy of inter-atomic bonds. The band structure, density of states and Fermi surfaces have been evaluated and discussed. Appreciable changes in the near-Fermi bands and the Fermi surface topology found as going from (Sr,Ba)Ru2As2 to (Sr,Ba)Rh2As2 reflect the growth of the 3D-like type of dispersion for these systems, which is accompanied by an increase in the near-Fermi density of states. The inter-atomic bonding in (Sr,Ba)(Ru,Rh)2As2 phases adopts a complex anisotropic character, where the bonding in [(Ru,Rh)2As2] blocks is of a mixed metallic-ionic-covalent type whereas between adjacent [(Ru,Rh)2As2] blocks and (Sr,Ba) atomic sheets, ionic interactions emerge; thus these systems may be classified as ionic metals.