The intrinsic low lattice thermal conductivities originates from the complex anion bonding environment make quaternary chalcogenides potential thermoelectric materials. Here, the bonding environment of Se atom in Cu_2.1Mn_0.9SnSe₄ is further regulated by substituting Mn²⁺ with equimolar pairing elements (Ag⁺ and In³⁺). The increase in both bond length and angle, together with the reduction in bond strength of Ag–Se and In–Se bonds, cause the doped samples to display strong anharmonicities (γ ∼ 1.84–2.04). And the weakened bond strength also lower the sound velocities. Consequently, the κ_L of the doped samples is effectively constrained, achieving a minimum value of 0.55 W⸱m^–1⸱K^–1 at 673 K in x = 0.10 sample. Ultimately, a zT value of 0.53 at 673 K is attained in x = 0.10 sample. The modification of bonding environment around anion is considered as an effective mean to optimize the thermoelectric performance of quaternary chalcogenides.

中文翻译：

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调整 Cu2MnSnSe4 基合金中 Se 原子的键合环境以提高热电性能


源于复杂阴离子键合环境的本征低晶格热导率使季硫系元素成为潜在的热电材料。在这里，通过将 Mn²⁺ 替换为等摩尔配对元素（Ag⁺ 和 In³⁺），进一步调节 Cu_2.1Mn_0.9SnSe₄ 中 Se 原子的键合环境。键长和角度的增加，以及 Ag-Se 和 In-Se 键的键强度降低，导致掺杂样品表现出强烈的不谐性 （γ ∼ 1.84–2.04）。而粘合强度的减弱也会降低声速。因此，掺杂样品的 κ_L 受到有效约束，在 x = 0.10 样品中的 673 K 时达到 0.55 W⸱m^–1⸱K^–1 的最小值。最终，在 x = 0.10 样品中，在 673 K 时获得 0.53 的 zT 值。改变阴离子周围的键合环境被认为是优化季硫族化合物热电性能的有效手段。