LOW-ENERGY EXCITATION IN CUI

Neutron inelastic scattering of the copper-ion conductor Cul is measured by the time-of-flight (TOF) method at 35, 200, 280 and 360-degrees-C. The neutron inelastic spectra are analyzed by the use of a model function for the generalized density of states. This model function consists of two components: a low-energy excitation mode and phonon modes due to the transverse acoustic branch. The value of the dispersionless low-energy excitation HomegaBAR almost-equal-to 3.4 meV is almost independent of temperature. The relation between the excitation energy and the mass of the cations can be represented by HomegaBAR almost-equal-to (1/M) 1/2. The relation could also be described as a cation plasma model with an appropriate effective charge of the cation.