Bonding Nature of Local Structural Motifs in Amorphous GeTe

Despite its simple chemical constitution and unparalleled technological importance, the phase‐change material germanium telluride (GeTe) still poses fundamental questions. In particular, the bonding mechanisms in amorphous GeTe have remained elusive to date, owing to the lack of suitable bond‐analys...

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Bibliographic Details
Published in:Angewandte Chemie International Edition 2014-09, Vol.53 (40), p.10817-10820
Main Authors: Deringer, Volker L., Zhang, Wei, Lumeij, Marck, Maintz, Stefan, Wuttig, Matthias, Mazzarello, Riccardo, Dronskowski, Richard
Format: Article
Language:English
Subjects:
Amorphous structure
bond theory
Bonding
Breaking down
Chemists
Covalent bonds
crystal orbital overlap populations
Crystal structure
Fragments
Intermetallics
molecular dynamics
phase-change materials
resistance drift
Tellurides
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Summary:Despite its simple chemical constitution and unparalleled technological importance, the phase‐change material germanium telluride (GeTe) still poses fundamental questions. In particular, the bonding mechanisms in amorphous GeTe have remained elusive to date, owing to the lack of suitable bond‐analysis tools. Herein, we introduce a bonding indicator for amorphous structures, dubbed “bond‐weighted distribution function” (BWDF), and we apply this method to amorphous GeTe. The results underline a peculiar role of homopolar GeGe bonds, which locally stabilize tetrahedral fragments but not the global network. This atom‐resolved (i.e., chemical) perspective has implications for the stability of amorphous “zero bits” and thus for the technologically relevant resistance‐drift phenomenon. Amorphous—no problem! Analyzing a crystalline structure by breaking it down into local fragments and covalent bonds is a technique that chemists have long perfected. With new tools at hand, this chemical language can be extended to amorphous solid‐state materials—in this case, to the phase‐change memory alloy germanium telluride.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.201404223