The Se substitution effect on Grneisen parameter (γ _G) of thermoelectric layered compound LaOBiS_2–x Se _x , whose highest dimensionless figure-of-merit is 0.36 at 650K, was investigated. From the estimated volume thermal expansion coefficient, bulk modulus, molar volume, and molar heat capacity at constant volume, γ _G was calculated as 0.88, 1.46, and 1.36 for x=0, 0.5, and 1.0, respectively. The increase in γ _G by Se substitution, obtained in this study, is consistent with the results obtained in previous neutron inelastic scattering experiments and proves enhanced lattice anharmonicity by Se substitution.

中文翻译：

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通过 Grneisen 参数研究热电 LaOBiS2-x Se x 中的晶格非谐性

研究了Se 取代对热电层状化合物LaOBiS _{2– x} Se _{x 的}Grneisen 参数( γ _G ) 的影响，其最高无量纲品质因数在650K 下为0.36。根据估计的体积热膨胀系数、体积模量、摩尔体积和恒定体积下的摩尔热容，对于x = 0、0.5和 1.0，γ _G分别计算为 0.88、1.46 和 1.36 。在本研究中获得的 Se 置换引起的γ _G增加与先前中子非弹性散射实验中获得的结果一致，并证明 Se 置换增强了晶格非谐性。