Initial structure memory of pressure-induced changes in the phase-change memory alloy Ge2Sb2Te5

We demonstrate that while the metastable face-centered cubic (fcc) phase of Ge2Sb2Te5 becomes amorphous under hydrostatic compression at about 15 GPa, the stable trigonal phase remains crystalline. Upon higher compression, a body-centered cubic phase is obtained in both cases around 30 GPa. Upon dec...

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Bibliographic Details
Published in:Physical review letters 2009-09, Vol.103 (11), p.115502-115502
Main Authors: Krbal, M, Kolobov, A V, Haines, J, Fons, P, Levelut, C, Le Parc, R, Hanfland, M, Tominaga, J, Pradel, A, Ribes, M
Format: Article
Language:English
Subjects:
Condensed Matter
Disordered Systems and Neural Networks
Physics
Online Access:Get full text
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Summary:We demonstrate that while the metastable face-centered cubic (fcc) phase of Ge2Sb2Te5 becomes amorphous under hydrostatic compression at about 15 GPa, the stable trigonal phase remains crystalline. Upon higher compression, a body-centered cubic phase is obtained in both cases around 30 GPa. Upon decompression, the amorphous phase is retained for the starting fcc phase while the initial structure is recovered for the starting trigonal phase. We argue that the presence of vacancies and associated subsequent large atomic displacements lead to nanoscale phase separation and loss of initial structure memory in the fcc staring phase of Ge2Sb2Te5.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.103.115502