Grünwald Michael, Rabani Eran, Dellago Christoph
Faculty of Physics and Center for Computational Materials Science, University of Vienna, Boltzmanngasse 5, 1090 Vienna, Austria.
Phys Rev Lett. 2006 Jun 30;96(25):255701. doi: 10.1103/PhysRevLett.96.255701. Epub 2006 Jun 27.
We study the pressure-driven phase transition from the four-coordinate wurtzite to the six-coordinate rocksalt structure in CdSe nanocrystals with molecular dynamics computer simulations. With an ideal gas as the pressure medium, we apply hydrostatic pressure to spherical and faceted nanocrystals ranging in diameter from 25 to 62 A. In spherical crystals, the main mechanism of the transformation involves the sliding of (100) planes, but depending on the specific surface structure we also observe a second mechanism proceeding through the flattening of (100) planes. In faceted crystals, the transition proceeds via a five-coordinated hexagonal structure, which is stabilized at intermediate pressures due to dominant surface energetics.
我们通过分子动力学计算机模拟研究了CdSe纳米晶体中从四配位纤锌矿到六配位岩盐结构的压力驱动相变。以理想气体作为压力介质，我们对直径在25至62埃范围内的球形和多面纳米晶体施加静水压力。在球形晶体中，转变的主要机制涉及（100）面的滑动，但根据特定的表面结构，我们还观察到通过（100）面的扁平化进行的第二种机制。在多面晶体中，转变通过五配位六边形结构进行，由于主导的表面能，该结构在中间压力下得以稳定。
