Chemical bonding in phase-change chalcogenides

Journal article

Almost all phase-change memory materials (PCM) contain chalcogen atoms, and their chemical bonds have been denoted both as ‘electron-deficient’ [sometimes referred to as ‘metavalent’] and ‘electron-rich’ [‘hypervalent’, multicentre]. The latter involve lone-pair electrons. We have performed calculations that can discriminate unambiguously between these two classes of bond and have shown that PCM have electron-rich, 3c–4e (‘hypervalent’) bonds. Plots of charge transferred between (ET) and shared with (ES) neighbouring atoms cannot on their own distinguish between ‘metavalent’ and ‘hypervalent’ bonds, both of which involve single-electron bonds. PCM do not exhibit ‘metavalent’ bonding and are not electron-deficient; the bonding is electron-rich of the ‘hypervalent’ or multicentre type.

Authors: Müller, PC; Elliott, SR; Dronskowski, R; Jones, RO

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: IOP Publishing
• Journal: Journal of Physics: Condensed Matter
• Volume: 36
• Issue: 32
• Article number: 325706
• Publication date: 2024-05-17
• Acceptance date: 2024-05-02
• DOI: 10.1088/1361-648x/ad46d6
• EISSN: 1361-648X
• ISSN: 0953-8984
• Language: English
• Keywords: quantum theory of atoms in molecules (QTAIM); chalcogenide materials; metavalency; chemical bonding; density functional calculations; phase-change materials; electron-rich multicentre (‘hypervalent’) bonding