The role of vacancies in the pressure amorphisation phenomenon observed in Ge-Sb-Te phase change alloys

M. Krbal, A. V. Kolobov, P. Fons, J. Tominaga, J. Haines, A. Pradel, M. Ribes, C. Levelut, R. Le Parc, M. Hanfland

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We demonstrate, both experimentally and by computer simulation, that while the metastable face-centered cubic (fcc) phase of Ge-Sb-Te becomes amorphous under hydrostatic compression at about 15 GPa, the stable trigonal phase remains crystalline. We present evidences that the pressure-induced amorphisation phenomenon strongly depends on the concentration of vacancies included in the Ge/Sb sublattice, but is thermally insensitive. Upon higher compression, a body-centered cubic phase is obtained in both cases at around 30 GPa. Upon decompression, the amorphous phase is retained when starting with the fcc phase while the initial structure is recovered when starting with the trigonal phase. We argue that the presence of vacancies and the associated subsequent large atomic displacements lead to nanoscale phase separation and the loss of the initial structure memory in the fcc staring phase of Ge-Sb-Te. We futher compare the amorphous phase obtained via the pressure route with the melt quenched amorphous phase.

Original languageEnglish
Title of host publicationPhase-Change Materials for Memory and Reconfigurable Electronics Applications
PublisherMaterials Research Society
Pages80-86
Number of pages7
ISBN (Print)9781617822186
DOIs
Publication statusPublished - 2010
Externally publishedYes

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1251
ISSN (Print)0272-9172

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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