Rb₃Er₄Cu₅Te₁₀: Exploring the Frontier between Polar Intermetallics and Zintl‐Phases via Experimental and Quantumchemical Approaches

Abstract

The tailored design of solid‐state materials requires a proper understanding of their respective electronic structures. In order to rationalize the relationships between crystal structures and electronic structures in intermetallic compounds, the Zintl‐Klemm concept has been frequently employed. Yet, the frontier between the valence‐electron concentrations (e/a) of the Zintl‐ and the polar intermetallic phases has remained unclear to date. To shed some light on this frontier, we explored the electronic structure of the quaternary compound Rb3Er4Cu5Te10. To this effect, the crystal structure of this telluride, which was obtained as pure phase from high‐temperature reactions, was determined by means of X‐ray diffraction experiments for the very first time. In addition, the magnetic properties of the Rb3Er4Cu5Te10 were also determined in order to explore the erbium 4 f states in more detail.

Exploring the Impact of Lone Pairs on the Structural Features of Alkaline‐Earth (A) Transition‐Metal (M,M’) Chalcogenides (Q) AMM'Q3

“…The aforementioned approach was also employed for full structural optimizations, which were completed prior to the examinations of the DOS as well as bonding analyses and included lattice parameters as well as atomic positions. Correlation and exchange were modelled by the generalized gradient approximation of Perdew, Burke, and Ernzerhof [47] (GGA‐PBE), while all computations were carried out in non‐magnetic regimes with the Gd‐4 f states treated as core‐like – an approach that has also been previously [7h] employed in first‐principles‐based computations on quaternary alkali‐metal rare‐earth copper tellurides. This method was chosen, because it is still hard to properly describe the strong correlations corresponding to the lanthanide 4 f electrons, even if a Hubbard U parameter [48] is included in the density‐functional‐theory‐based calculations.…”

Exploring the subtle factors that control the structural preferences in Cu7Te4

“…Clearly, the Cu-Cu interactions show a less bonding character relative to the Cu-Te interactions due to the nature of the d 10 -d 10 interactions as typically [98][99][100][101] encountered for homoatomic Cu-Cu contacts. The heteroatomic Cu-Te interactions exhibit a strongly bonding character pointing to a covalent bonding nature with the valence-electrons being located between the copper and tellurium atoms.…”