A quaternary narrow-band-gap semiconductor, Ba₂Cr₄GeSe₁₀, has been discovered by solid-state reaction. It features a new structure type and crystallizes in the triclinic space group P1̅ (No. 2). The featured 2D anionic layers are constructed by condensed CrSe₆ octahedra that are stacking along the c axis, with dispersed GeSe₄ tetrahedra and located Ba²⁺ cations forming these layers. The energy-band structure shows a clear separation between the region of electronic conduction and the zone of electronic insulation. Significantly, an undoped Ba₂Cr₄GeSe₁₀ sample shows a desirable low thermal conductivity κ_T (0.51–0.87 W/m·K) and a high Seebeck coefficient S (351–404 μV/K) and reaches a ZT ≈ 0.08 at 773 K.

中文翻译：

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四元层状半导体Ba ₂ Cr ₄ GeSe _10的合成，晶体结构和热电性质

通过固相反应发现了一种四级窄带隙半导体Ba ₂ Cr ₄ GeSe ₁₀。它具有新的结构类型和结晶在三斜晶系空间群P 1（2号）。精选的2D阴离子层由沿c轴堆叠的稠密CrSe ₆八面体，分散的GeSe ₄四面体和定位的Ba ²⁺阳离子构成。能带结构显示出电子传导区域和电子绝缘区域之间的清晰分隔。值得注意的是，未掺杂的Ba ₂ Cr ₄ GeSe ₁₀样品示出了期望的低的热导率κ _Ť（0.51-0.87瓦/米·K）和高的塞贝克系数小号（351-404μV/ K）并达到ZT ≈0.08在773 K.