Low energy vibrational excitations characteristic of superionic glass

The mechanism of high ionic conductivity in superionic glass constitutes an unsolved problem in the field of science. Here we performed inelastic neutron scattering measurements of superionic glass system ( AgI ) x ( Ag 2 S ) x ( AgPO 3 ) 1 - 2 x by using MARI spectrometer at ISIS, and found that the Q -dependence of inelastic intensity in the energy region from 1 to 3 meV of superionic phase glass shows an excess intensity above Q = 1.8 Å - 1 compared with insulator phase. Similar phenomena were also observed in another superionic glass ( AgI ) 0.5 ( AgPO 3 ) 0.5 by using NEAT spectrometer at HMI with high resolution measurement. These results clearly suggest peculiar low energy vibrational excitations should be universal features of superionic glass.