Electrical Characterization of Pressure Induced Phase Transitions in Mercury Chalcogenides

The widths of the hystereses curves, characterizing the pressure induced phase transitions of mercury chalcogenides, were substantiaily decreased by the addition of nucleation centers. A quantitative influence of the concentration of these nuclei on the offset transition pressures was established in the cases of the phase transitions of HgSe. A direct technique, based on resistance discontinuity, was used and correlated to volumetric measurements. A polynucleation model was developed and the critical sizes of the nuclei are suggested to be related to the "region of indifference" defined by Bridgman. The developed conversion function was verified on the experimental data obtained by detecting the pressure induced polymorphic phase transition simultaneously by resistance and volumetric discontinuity techniques.