Regensburg 2019 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 14: Poster

DS 14.23: Poster

Dienstag, 2. April 2019, 17:00–20:00, Poster E

Unraveling the interplay of structure and electronic properties in the phase-change material compound family of GST — •Carl-Friedrich Schön, Matthias Dück, and Matthias Wuttig — I. Physikalisches Institut (IA), RWTH Aachen University, D-52056 Aachen, Germany

Phase-change materials (PCM) are a promising candidate for universal memory, as their optical reflectivity and electrical resistivity change considerably between the amorphous and the crystalline state. Devices utilizing that transition have recently been realized in the form of the Micron/Intel Optane Memory. It is even more intriguing that some PCMs of the GeTe-SbTe compound family (GST) show the transition from insulating to metallic behavior (MIT) within the crystalline phase. Interlinked with disorder effects, this MIT's nature is unprecedentedly Anderson-like. While the understanding of the electronic properties is paramount, assumptions regarding band shape, effective mass and degeneracy at the L-point have yet to be proven. In this work, film thickness and the degree of disorder in terms of vacancy type, quantity and arrangement of GST thin films are varied. Growth control and structural characterization are employed to map the properties across the MIT, which is induced by the redistribution of randomly distributed vacancies to vacancy layers. The goal is to unravel the interplay of structure, morphology, band structure and electronic properties to gain insights into the mechanisms driving the MIT. The findings of this work are aimed to support the development of analogue neural computing units and multi-state memory devices.