Shape change as an indicator of mechanism in the high-pressure structural transformations of CdSe nanocrystals

X-ray diffraction was used to monitor the structure of 45 A diameter CdSe nanocrystals as they transformed repeatedly between fourfold and sixfold coordinated crystal structures. Simulations of the diffraction patterns reveal that a shape change occurs as the crystals transform. They also show that stacking faults are generated in the transition from the high- to the low-pressure phase. The shape change and stacking fault generation place significant constraints on the possible microscopic mechanism of the phase transition.