TEM study of the structural similarity between NaCl and rhombohedral phase of Te-based ternary chalcogenide materials

Comparing the phase-change behaviour of Ge-Bi-Te(GBT) to that of Ge-Sb-Te(GST), we have tried to verify a general relationship between a metastable NaCl and a stable rhombohedral structure that is easily incurred by stretching the cube along the body diagonal. High-resolution transmission electron microscopy (TEM) images show that the NaCl as well as the rhombohedral GBT and GST structures are observed along specific directions. From the TEM images, we suggest an atomic model and a phase transition mechanism by lattice distortion. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)