Article abstract
Nature Materials 7, 653 - 658 (2008)
Published online: 11 July 2008 | doi:10.1038/nmat2226
Subject Categories: Electronic materials | Semiconductors | Optical, photonic and optoelectronic materials
Resonant bonding in crystalline phase-change materials
Kostiantyn Shportko1, Stephan Kremers1, Michael Woda1, Dominic Lencer1, John Robertson2 & Matthias Wuttig1,3
Abstract
The identification of materials suitable for non-volatile phase-change memory applications is driven by the need to find materials with tailored properties for different technological applications and the desire to understand the scientific basis for their unique properties. Here, we report the observation of a distinctive and characteristic feature of phase-change materials. Measurements of the dielectric function in the energy range from 0.025 to 3 eV reveal that the optical dielectric constant is 70–200% larger for the crystalline than the amorphous phases. This difference is attributed to a significant change in bonding between the two phases. The optical dielectric constant of the amorphous phases is that expected of a covalent semiconductor, whereas that of the crystalline phases is strongly enhanced by resonant bonding effects. The quantification of these is enabled by measurements of the electronic polarizability. As this bonding in the crystalline state is a unique fingerprint for phase-change materials, a simple scheme to identify and characterize potential phase-change materials emerges.
- Institute of Physics (IA), RWTH Aachen University, 52056 Aachen, Germany
- Engineering Department, Cambridge University, Cambridge CB2 1PZ, UK
- JARA-FIT, RWTH Aachen University, 52056 Aachen, Germany
Correspondence to: Matthias Wuttig1,3 e-mail: wuttig@physik.rwth-aachen.de
MORE ARTICLES LIKE THIS
These links to content published by NPG are automatically generated.
NEWS AND VIEWS
Phase-change materials Designing optical media of the futureNature Materials News and Views (01 Feb 2007)
Information storage Around the phase-change cycleNature Materials News and Views (01 May 2008)
See all 9 matches for News And ViewsRESEARCH
Supplementary InformationNature Materials Article (01 Dec 2008)
Understanding the phase-change mechanism of rewritable optical mediaNature Materials Article (01 Oct 2004)
See all 26 matches for Research
