Temperature and Pressure Effect on the Absorption Edge in (Sn 0.95 Zn 0.05 ) 2 P 2 S 6 Crystal

The shape of the fundamental optical absorption edge as well as its temperature and pressure dependences in the vicinity of phase transitions in (Sn0.95Zn0.05)(2)P2S6 ferroelectric crystals are studied. The (p, T) phase diagram of (Sn0.95Zn0.05)(2)P2S6 crystals has been proposed based on these data.