Chemical bonding in phase-change chalcogenides

Journal of Physics Condensed Matter, vol. 36, pp. 325706

Abstract

Abstract 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 4

1. Peter C. Müller Aachen Lehrstuhl für Festkörper- and Quantenchemie Institut für Anorganische Chemie

   RWTH Aachen University

   Affiliation as printed

   Lehrstuhl für Festkörper- and Quantenchemie, Institut für Anorganische Chemie, RWTH Aachen University, D-52056 Aachen, Germany

2. Stephen R. Elliott

   University of Oxford

   Affiliation as printed

   Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford OX1 3QZ, United Kingdom

3. Richard Dronskowski Aachen Lehrstuhl für Festkörper- and Quantenchemie Institut für Anorganische Chemie

   RWTH Aachen University

   Affiliation as printed

   Lehrstuhl für Festkörper- and Quantenchemie, Institut für Anorganische Chemie, RWTH Aachen University, D-52056 Aachen, Germany

4. R. Jones

   Forschungszentrum Jülich

   Affiliation as printed

   Peter-Grünberg-Institut PGI-1, Forschungszentrum Jülich, D-52425 Jülich, Germany