Fig. 2: Anomalies in atomic displacement parameters and heat capacities.
From: Vacancies tailoring lattice anharmonicity of Zintl-type thermoelectrics
a–c Overall isotropic atomic displacements, \({B}_{{{{{{\rm{ov}}}}}}}\), of the Sr(Cu,Ag,Zn)Sb compounds fitted with a modified Debye−Einstein model (Supplementary Note 1 and Supplementary Tables 4). The error bars are estimated from the standard deviation of the Rietveld refinements. d–f Heat capacities, \({C}_{P}\), of Sr(Cu,Ag,Zn)Sb fitted with one Debye mode, three Einstein modes plus an individual contribution from electrons (Supplementary Note 2 and Supplementary Table 5). The Debye and three Einstein modes are denoted as \({{{{{\rm{D}}}}}}\), \({{{{{\rm{E}}}}}}1\), \({{{{{\rm{E}}}}}}2\) and \({{{{{\rm{E}}}}}}3\), respectively. The Debye and Einstein temperatures, \({\varTheta }_{{{{{{\rm{D}}}}}}}\) and \({\varTheta }_{{{{{{\rm{E}}}}}}}\), are given in (a–f) from the fittings of \({B}_{{{{{{\rm{ov}}}}}}}\) and \({C}_{P}\). \(\beta\) represents the electronic contribution to the heat capacity. g \({C}_{P}/{T}^{3}\) vs \(T\) (2–50 K) plot shows broad peak, demonstrating the necessity of the combined Debye-Einstein model in the fitting (Supplementary Fig. 8). Source data are provided as a Source Data file.
