New layered quaternary Zintl pnictide oxides Ba2Zn2Pn2O (Pn = Sb, Bi): Discovery, crystal structures, band engineering, and transport properties

Document Type

Article

Publication Date

11-1-2025

Abstract

Three new heteroanionic oxypnictides, Ba2Zn2Sb2O, Ba2Zn2Bi2O, and the solid solution Ba2Zn2Sb2−xBixO (x ≈ 1.1–1.6), have been synthesized and structurally characterized. They are isostructural with their Mn-bearing analog, adopting the Ba2Mn2Sb2O-type structure (space group P63/mmc, No. 194), and feature a double-layered 2D 2∞ [Zn2Pn2O]2- substructure (Pn = Sb, Bi, Sb/Bi) composed of corner-sharing, distorted tetrahedral ZnPn3O units. Electronic structure calculations reveal a systematic progression from semiconducting Ba2Zn2Sb2O to metallic Ba2Zn2Bi2O as Bi content increases. These trends are corroborated by transport property measurements, with Ba2Zn2Sb0.9(1)Bi1.1O exhibiting relatively low electrical resistivity, high Hall mobilities of ∼160 cm2/V·s, and large Seebeck coefficients from 69 to 132 μV K−1 over the 300–600 K temperature range. Comparison with structurally related Zintl pnictides, such as SrIn2As2 and PrZn3As3 phases, situates Ba2Zn2Pn2O (Pn = Sb, Bi) within a broader family of heteroanionic oxypnictide Zintl compounds, highlighting their structural flexibility and amenability to band engineering. Electronic structure and bonding considerations point to tunable semiconducting behavior and underscore the relevance of these materials for thermoelectric and topological applications.

Publication Source (Journal or Book title)

Solid State Sciences

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