Theory of the Superionic Transition in CuI

概要

論文の詳細を見る
The direct transition from the γ-phase to the α-phase in CuI, the superionic transition, is studied in terms of the dependence of the free energy on the order parameter and temperature. The average structure of the α-phase is expressed by a microcrystalline model to take into account the Cu+–Cu+ Coulomb correlation. The formation energy of microcrystals is expressed as the surface energy, and calculated from the interionic interaction, which consists of Vashishta-Rahman's potential and nearest neighbour covalent bond. Anharmonic vibration of Cu+ is described by Einstein model with cubic anharmonicity. The transition entropy comes from the configuration of microcrystals and increase of thermal vibration of Cu+ on a microcrystal surface. The calculated transition entropy and energy per ion pair are 1.4 kB and 0.11 eV, respectively, which are close to the observed values.
社団法人日本物理学会の論文