title: Bonding nature of local structural motifs in amorphous GeTe.
abstract: 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.
authors.affiliation: Institute of Inorganic Chemistry, RWTH Aachen University, Landoltweg 1, 52056 Aachen (Germany).
authors.forename: Volker L
authors.initials: VL
authors.lastname: Deringer
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Marck
authors.initials: M
authors.lastname: Lumeij
authors.forename: Stefan
authors.initials: S
authors.lastname: Maintz
authors.forename: Matthias
authors.initials: M
authors.lastname: Wuttig
authors.forename: Riccardo
authors.initials: R
authors.lastname: Mazzarello
authors.forename: Richard
authors.initials: R
authors.lastname: Dronskowski
keywords: bond theory; crystal orbital overlap populations; molecular dynamics; phase-change materials; resistance drift