We demonstrate that the Ge(Sb)-Te bond lengths in crystallized cubic Ge2Sb2Te5 (GST) are significantly lower than the values expected from the previous X-ray diffraction (XRD) analysis. At the same time, the second nearest-neighbour Te-Te distances are in perfect agreement with XRD. We conclude that the structure of GST is a distorted rocksalt structure. Upon amorphization, Ge-Te and Sb-Te bonds get shorter and stronger. This unusual behaviour is due to a switch of Ge atom from an octahedral symmetry position in the crystalline state into a tetrahedral symmetry position in the amorphous state. It is this switching of the Ge atoms that is responsible for the fast and stable media performance.
|Number of pages||6|
|Journal||Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms|
|Publication status||Published - 2006 May 1|
ASJC Scopus subject areas
- Nuclear and High Energy Physics