Tetrahedral germanium in amorphous phase change materials

Exploring the isochemical scenario

Matthieu Micoulaut, Ali Kachmar, Thibault Charpentier

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The structural, vibrational, and electronic properties of low-temperature supercooled GeTe 4 are studied using density functional theory (DFT). Two models have been considered: an ordinary melt-quenched system containing a majority of defect-octahedral germanium atoms, and a relaxed one obtained from a quenched SiTe 4 rescaled structure which contains mostly tetrahedral germanium, while leaving the Te environment preserved. The tetrahedral system exhibits an increased agreement with the experimental structure factor S(k), the pair distribution function g(r), and the infrared absorption spectrum. It is suggested that the fraction of tetrahedral Ge must be higher as usually believed. In addition, we provide the calculation of the 125Te wideline NMR spectra. While the latter do not agree with recent experimental findings, both systems exhibit important significant differences in the widths of the computed spectra. These exploratory calculations clearly show that NMR will be an interesting probe that deserves further investigations for the experimental determination of the local geometry.

Original languageEnglish
Pages (from-to)1890-1896
Number of pages7
JournalPhysica Status Solidi (B) Basic Research
Volume249
Issue number10
DOIs
Publication statusPublished - Oct 2012
Externally publishedYes

Fingerprint

Germanium
phase change materials
Phase change materials
germanium
Nuclear magnetic resonance
nuclear magnetic resonance
Infrared absorption
Electronic properties
infrared absorption
Distribution functions
Density functional theory
Absorption spectra
infrared spectra
distribution functions
density functional theory
absorption spectra
Atoms
Defects
Geometry
probes

Keywords

  • Molecular dynamics simulations
  • Phase change materials
  • Structure
  • Supercooled liquids

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Tetrahedral germanium in amorphous phase change materials : Exploring the isochemical scenario. / Micoulaut, Matthieu; Kachmar, Ali; Charpentier, Thibault.

In: Physica Status Solidi (B) Basic Research, Vol. 249, No. 10, 10.2012, p. 1890-1896.

Research output: Contribution to journalArticle

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