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The local structural differences in amorphous Ge-Sb-Te alloys
- Source :
- Journal of Alloys and Compounds. 774:748-757
- Publication Year :
- 2019
- Publisher :
- Elsevier BV, 2019.
-
Abstract
- Chalcogenide alloys in pseudobinary line between Sb2Te3 and GeTe are extensively utilied in phase change memories for optical and electronic contrast between crystalline and amorphous phases. Different from the crystalline structure, the understanding of amorphous structures is still insufficient due to disorder and distortion. By employing first-principle molecular dynamics simulations and atomistic cluster alignment analysis, the short-range orders and the associated distortions of amorphous Sb2Te3, Ge1Sb2Te4, Ge2Sb2Te5, Ge3Sb2Te6 and GeTe are investigated to explore the origin of nature difference. The results reveal that Ge Ge and Sb Sb bonds present a notable competitive mechanism with GeTe content. The GeTe content has a great influence on Ge- and Te-centered short-range orders but little influence on the structures of Sb-centered clusters, especially for the octahedral sites and unidentified structures. The tetrahedrons in Ge-centered clusters of each alloy show a close proportion, but the fraction of tetrahedrons in total clusters increases with the increasing GeTe content due to the increase in the ratio of Ge atom. As for the distortions of clusters, the distorted tetrahedrons in Ge2Sb2Te5 are closest to the standard tetrahedron, the Peierls distortion of Ge-centered 6-fold octahedron reduces with an increase in GeTe content whereas that of Sb-centered 6-fold octahedron shows a little change. Additionally, it is found that GeTe content can inhibit the formation of nanocavity but contribute to the formation of the odd rings. Our findings deepens the understanding of amorphous structures, which can promote the design and application of phase-change materials.
- Subjects :
- Materials science
Chalcogenide
Mechanical Engineering
Alloy
Metals and Alloys
02 engineering and technology
Crystal structure
engineering.material
010402 general chemistry
021001 nanoscience & nanotechnology
01 natural sciences
0104 chemical sciences
Amorphous solid
Molecular dynamics
chemistry.chemical_compound
chemistry
Octahedron
Mechanics of Materials
Chemical physics
Atom
Materials Chemistry
Cluster (physics)
engineering
0210 nano-technology
Subjects
Details
- ISSN :
- 09258388
- Volume :
- 774
- Database :
- OpenAIRE
- Journal :
- Journal of Alloys and Compounds
- Accession number :
- edsair.doi...........5b2183951304c0038e8627e389ec4093