Anomalous temperature dependency of the Anderson–Grüneisen parameters in high ionic conductors

The Anderson–Grüneisen (AG) parameter carries information on the anharmonicity of the atomic vibrations of the materials. Therefore, its study is expected to provide useful insights to understand the ion transport properties in solids. However, few attentions on the AG parameter of ionic conductors have been paid till now. In the present paper, a comparative study on the temperature dependence of the AG parameter in superionic materials and other crystals is presented. It is shown that the AG parameter of superionic materials exhibit anomalously large temperature dependencies. The relations of this finding with the material properties of ionic conductors are briefly discussed.