Dresden 2009 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 48: Poster 2

HL 48.7: Poster

Donnerstag, 26. März 2009, 15:00–17:30, P2

A Treasure Map for Phase-Change Materials — •Dominic Lencer¹, Martin Salinga¹, Blazej Grabowski², Tilmann Hickel², Jörg Neugebauer², and Matthias Wuttig¹ — ¹JARA-FIT, RWTH Aachen, I. Physikalisches Institut (IA), 52056 Aachen — ²Max-Planck Institut für Eisenforschung, 40237 Düsseldorf

Phase-change materials are characterized by a unique property portfolio well suited for data storage applications. They exhibit a pronounced optical and electrical contrast between the crystalline and the amorphous state. In a recent study, we have identified the occurrence of resonance bonding in the crystalline state as being responsible for the optical contrast. The search for novel phase-change materials can hence be redirected to materials exhibiting resonance bonding. In order to supplement this effort, we introduce a coordinate scheme [1] based on the work of P. B. Littlewood. It is spanned by two coordinates calculated just from the composition. These coordinates represent the degree of ionicity and the tendency towards hybridization (covalency) of the bonding. A small magnitude of both quantities is an inherent characteristic of phase-change materials and marks the region of this map, where resonance bonding occurs. Furthermore, this map also enables a prediction of trends for the physical properties upon changing stoichiometry.

[1] Lencer, D., Salinga, M., Grabowski, M., Hickel, T., Neugebauer, J. & Wuttig, M. A Map for Phase-Change Materials. Nature Materials, in the press (2008).