This title appears in the Scientific Report :
2008
Please use the identifier:
http://dx.doi.org/10.1088/0953-8984/20/46/465103 in citations.
Density functional study of amorphous, liquid and crystalline Ge2Sb2Te5: homopolar bonds and/or AB alternation?
Density functional study of amorphous, liquid and crystalline Ge2Sb2Te5: homopolar bonds and/or AB alternation?
The amorphous, liquid and crystalline phases of the phase change material Ge(2)Sb(2)Te(5) (GST) have been studied by means of density functional/molecular dynamics simulations. The large sample (460 atoms and 52 vacancies in the unit cell) and long simulations (hundreds of picoseconds) provide much...
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Personal Name(s): | Jones, R. O. |
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Akola, J. | |
Contributing Institute: |
Quanten-Theorie der Materialien; IAS-1 JARA-FIT; JARA-FIT Quanten-Theorie der Materialien; IFF-1 |
Published in: | Journal of physics / Condensed matter, 20 (2008) S. 465103 |
Imprint: |
Bristol
IOP Publ.
2008
|
Physical Description: |
465103 |
DOI: |
10.1088/0953-8984/20/46/465103 |
PubMed ID: |
21693837 |
Document Type: |
Journal Article |
Research Program: |
Grundlagen für zukünftige Informationstechnologien |
Series Title: |
Journal of Physics: Condensed Matter
20 |
Subject (ZB): | |
Publikationsportal JuSER |
The amorphous, liquid and crystalline phases of the phase change material Ge(2)Sb(2)Te(5) (GST) have been studied by means of density functional/molecular dynamics simulations. The large sample (460 atoms and 52 vacancies in the unit cell) and long simulations (hundreds of picoseconds) provide much new information. Here we extend our original analysis (2007 Phys. Rev. B 76 235201) in important ways: partial coordination numbers and radial distribution functions, bond angle distributions, new local order parameters, vibration frequencies, and the charges on atoms and vacancies. The valence band densities of states in amorphous and crystalline GST are compared with ones from x-ray photoemission spectroscopy. The results for the liquid phase are new and those for the crystalline phase much expanded. GST shows pronounced AB alternation (A: Ge, Sb; B: Te), especially in its amorphous phase, and ABAB squares play a central role in the amorphous to crystalline transition. We comment on earlier speculations concerning the nature of the amorphous to crystalline transition. |