Distortion of Local Atomic Structures in Amorphous Ge-Sb-Te Phase Change Materials

A. Hirata, T. Ichitsubo, P. F. Guan, T. Fujita, M. W. Chen

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


The local atomic structures of amorphous Ge-Sb-Te phase-change materials have yet to be clarified and the rapid crystal-amorphous phase change resulting in distinct optical contrast is not well understood. We report the direct observation of local atomic structures in amorphous Ge2Sb2Te5 using "local" reverse Monte Carlo modeling dedicated to an angstrom-beam electron diffraction analysis. The results corroborated the existence of local structures with rocksalt crystal-like topology that were greatly distorted compared to the crystal symmetry. This distortion resulted in the breaking of ideal octahedral atomic environments, thereby forming local disordered structures that basically satisfied the overall amorphous structure factor. The crystal-like distorted octahedral structures could be the main building blocks in the formation of the overall amorphous structure of Ge-Sb-Te.

Original languageEnglish
Article number205502
JournalPhysical Review Letters
Issue number20
Publication statusPublished - 2018 May 18


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