Nanometer-scale mechanism of phase-change optical recording as revealed by XAFS

A. V. Kolobov, P. Fons, J. Tominaga, A. I. Frenkel, A. L. Ankudinov, T. Uruga

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


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.

Original languageEnglish
Pages (from-to)69-74
Number of pages6
JournalNuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
Issue number1
Publication statusPublished - 2006 May 1
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Instrumentation


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