Mechanism of the high-pressure phase transitions from tetrahedrally bonded semiconductors to rocksalt – Maosheng Miao
Date: Mon. October 7th, 2002, 12:30 pm-1:30 pmLocation: Rockefeller 221
A uniform description is presented for the transition paths of various tetrahedrally bonded semiconductor structures, including wurtzite, zind blende and various SiC polytypes, to the high-pressure rocksalt phase. The enthalpy barriers for these strain induced transitions were calculated from first-principles. A relation between the sound velocity pressure coefficients and the strains that drive the phase transition is pointed out. This relation replaces the Weinstein model which related these transitions to a softening of the transverse acoustic phonons at the zone boundary.