Kinetics of phase transitions under high pressure

Abstract

Phase transitions under high pressure have attracted increasing attention i n connection with high pressure synthesis of new materials (e.g. superhard materials, ceramics, semiconductors, high temperature superconductors) and the exploration of geological processes like the formation of rocks and minerals. For t h e investigation of thermodynamic and electronic equilibrium properties a broad spectrum of methods for pressure generation and physical measurements have been developed ^1,2,3,4. Tha measurement of equilibrium properties, however, gives only poor insight into the detailed mechanisnts of phase changes. The accurate determination of phase equilibria and phase diagrams becomes inore and more difficult a t low temperatures due to increasing hysteresis effects end t h e extrapolation of experimental data to zerc, teiiipwature a nd the compar ison with quantumiiiechanical ah in.itio calculations are questionable.