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Phase-change materials for rewriteable data storage

An Erratum to this article was published on 13 November 2007

Abstract

Phase-change materials are some of the most promising materials for data-storage applications. They are already used in rewriteable optical data storage and offer great potential as an emerging non-volatile electronic memory. This review looks at the unique property combination that characterizes phase-change materials. The crystalline state often shows an octahedral-like atomic arrangement, frequently accompanied by pronounced lattice distortions and huge vacancy concentrations. This can be attributed to the chemical bonding in phase-change alloys, which is promoted by p-orbitals. From this insight, phase-change alloys with desired properties can be designed. This is demonstrated for the optical properties of phase-change alloys, in particular the contrast between the amorphous and crystalline states. The origin of the fast crystallization kinetics is also discussed.

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Figure 1: Rewriteable optical data storage using phase-change materials.
Figure 2
Figure 3: Crystal structures.

© 2001 APS

Figure 4: Schematic presentation of the possible ring structure transformation in the phase changes crystal–liquid–amorphous (record) and amorphous–crystal (erase) in Ge2Sb2Te5 and GeTe.

© 2006 AIP

Figure 5: Time–temperature–transformation diagram of an undercooled liquid.
Figure 6: Change of refractive index (n) and absorption coefficient (k) with stoichiometry for a wavelength of 405 nm.
Figure 7: Comparison of optics, recording densities, recording capacities and disk structures used for CD, DVD and BD.
Figure 8: Typical current–voltage curve of a phase-change alloy that was initially in the amorphous state.

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Acknowledgements

We thank J. Kalb and M. Salinga for critical reading of the manuscript and the European project WIND for financial support.

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Wuttig, M., Yamada, N. Phase-change materials for rewriteable data storage. Nature Mater 6, 824–832 (2007). https://doi.org/10.1038/nmat2009

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