Layered Quaternary Germanides—Synthesis and Crystal and Electronic Structures of AELi₂In₂Ge₂ (AE = Sr, Ba, Eu)

Abstract

Three new quaternary germanides with the composition AELi2In2Ge2 (AE = Sr, Ba, Eu) have been synthesized and structurally characterized. The layered crystal structure of these phases features homoatomic In–In bonding, but there are no direct Ge–Ge bonds. Such a crystallographic arrangement can be regarded as an ordered quaternary derivative of the CaCu4P2 structure (trigonal syngony, Pearson code hR7). Comprehensive analysis of the structural genealogy suggests relationships with the structures of other layered pnictides and chalcogenides, which are discussed. Partitioning of the available valence electrons and the assignment of the formal charges indicate that the composition of the new germanides is charge-balanced. First-principles calculations and electrical transport measurements indicate poor metallic behavior, resulting from significant hybridization of the electronic states.

Antiferromagnetic semiconductor Eu3Sn2P4 with Sn–Sn dimer and crown-wrapped Eu

“…8,9,40 Many series of these compounds, for example BaCaX (X = Si, Ge, Sn and Pb, Group IV), XNiSn and XCoSb (X = Ti, Zr or Hf), AELi 2 In 2 Ge 2 (AE = Sr, Ba, Eu), exhibit a crossover from semiconducting to metallic behavior upon doping or alloying with larger atomic sizes and heavier atoms. [41][42][43] It should be noted that varying U value does not change qualitatively results of the electronic structure calculations in Eu 3 Sn 2 P 4 . However, the size of the gap is sensitive to the value of the U parameter, due to changes of the energy separation, e.g.…”

Bismuth as a Reactive Solvent in the Synthesis of Multicomponent Transition-Metal-Bearing Bismuthides

“…When possible, the application of fluxes containing exclusively those elements that constitute the targeted crystals is beneficial because it allows one to avoid the presence of foreign elements in the product. In this way, many compounds of low-melting metals, e.g., gallium, indium, and tin, can be produced using the respective metal as a reactive flux. ,− …”

Synthesis, crystal and electronic structure of BaLixCd13–x (x ≈ 2)

“…In recent papers, we described new results from our exploratory work in the Ba-Li-In-Ge (Ovchinnikov and Bobev, 2019) and Ba-Li-Cd-Ge systems (Baranets et al, 2021b). As noted therein, our synthetic approach employed molten In and Cd as metal fluxes, allowing us to grow crystals of the quaternary phases, BaLi 2+x In 2-x Ge 2 (0 ≤ x ≤ 0.66) and BaLi 2 Cd 2 Ge 2 (CaCu 4 P 2 type, space group R 3 m; Pearson code hR7).…”