BIEXCITONIC LIQUID IN MONOCLINIC ZINC DIPHOSPHIDE CRYSTALS

The dielectric gas-dielectric liquid phase transition in the system of excitonic molecules in beta - ZnP2 crystals is considered. The influe nce of crystal anisotropy is under discussion. The features of beta - ZnP2 photoluminescence (PL) spectra under intermediate excitation inte nsities (I-exc similar to 10(3) - -10(5)W/cm(2)) at liquid helium temp eratures are considered. In previous works optical manifestations of t he dielectric biexcitonic liquid have been observed. An experimental s tudy of the phase diagram of this liquid is performed. Biexcitonic liq uid critical parameters are estimated.