ABSTRACT
We have measured far-infrared reflectivity spectra of single crystal CsPbClg below and above the superionic transition temperature Tc and determined the frequencies of optical phonons and optical dielectric constant ε∞. At 40 K, several bands and a low energy mode have been observed. Clear correlationships are established between ε ∞ and the activation energy Eac, and also between the effective charge and Eac value. Based on these, the cause for high ionic(HI) conduction in CsPbCl3 is attributed to the specific electronic structure near the band gap, similar to cation superionic conductor(SIC).
