Nonequilibrium Phase Transformations in Diamond and Zincblende Semiconductors under High Pressure

The problem of nonequilibrium phase transformations is reviewed for compression of diamond, zincblende, and amorphous tetrahedral semiconductors and for decompression of their high‐pressure phases. The importance of lattice or network dynamical properties for the nature of nonequilibrium transformations is shown. Using low‐temperature quenching of high‐pressure phases, we obtained new Crystalline phases for Ge and Ge‐Gash solid solutions, which have X‐ray patterns very similar to corresponding data for rhombohedral R8 silicon. We established that a number of anomalous features, like elastic softness, pressure‐induced geometrical distortion, and strong bulk modulus softening (δ B /δ P > 0), distinguish the pressure behavior of the amorphous tetrahedral network in a‐GaSb from its crystalline counterpart.