Automated portable high-pressure setup for study of phase transitions in solids

The automated portable high-pressure setup developed for combined measurements of several properties of solids at ultrahigh pressure is discussed. The setup produces a high quasi-hydrostatic pressure P (0–30 GPa) and permits to perform electrical, thermal and dilatometric measurements simultaneously. The setup registers changes both in electron and crystal structures of sample under nearly continuous variation of pressure. The results obtained demonstrate the advantages of the setup in studying both phase transformations and multiphase states in solids. The novel features of phase transitions in Si and ZnTe have been found. For silicon and zinc telluride, both the signs and values of thermoelectric power S (Seebeck coefficient) of the several high-pressure phases have been established in the pressure range of 0–20 GPa. In ZnTe, a novel transient high-pressure phase has been observed of electron type of conductivity between the high-pressure trigonal (cinnabar) and orthorhombic (Cmcm) ones. Multiphase states of the semiconductors in vicinity of the structural transitions were analysed in the terms of the multiphase model of “orientated inclusions” permitting to vary configuration and concentration of phase inclusions.