DIELECTRIC, CHARGE AND PHASE-SEPARATION INSTABILITIES IN PSEUDOSPIN-ELECTRON MODEL OF HIGH-T-C SUPERCONDUCTORS

The possible instabilities in high-T-c superconductors as well as thei r low-frequency dynamics are analyzed within the pseudospin-electron m odel involving Hubbard-type electron correlations and local anharmonic vibrations. The instabilities with respect to polarization and/or cha rge fluctuations caused by the effective interactions via conducting e lectrons are obtained from the temperature dependencies of the dynamic susceptibilities calculated in the generalized random phase approxima tion. The corresponding changes in the low-energy spectrum are investi gated.