Raman study of the mixed crystals CuxAg1-xI

Abstract
Raman spectra of the mixed crystals CuxAg1-xI are presented as a function of temperature and hydrostatic pressure. The low-temperature (15K) optical phonon spectrum shows a two-mode behaviour, including also a weak disorder-induced mode. Only one of the two thermally activated optical phonons of AgI appears in the high-temperature spectra (80K+ ions at off-centre sites. The room-temperature pressure-dependent measurements (up to 9 kbar) reveal a phase transition to the rocksalt structure in crystals with x<0.50.