Berlin 2018 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 65: Functional Materials (Actuators, filters, sensors, shape memory)

MM 65.4: Vortrag

Donnerstag, 15. März 2018, 18:15–18:30, H 0106

In situ observations on dynamic reconfiguration of bilayer defects in van der Waals bonded Ge-Sb-Te based alloys — •Andriy Lotnyk¹, Ulrich Ross¹, Torben Dankwort², Isom Hilmi¹, Lorenz Kienle², and Bernd Rauschenbach^1,3 — ¹Leibniz Institute of Surface Engineering (IOM), Permoserstr. 15, 04318 Leipzig, Germany — ²Institute for Materials Science, Faculty of Engineering, University of Kiel, Kaiserstr. 2, 24143 Kiel, Germany — ³Felix Bloch Institute for Solid State Physics, Leipzig University, Linnéstr. 5, 04103 Leipzig, Germany

Ge-Sb-Te (GST) based phase change alloys are well-known materials from optical data storage applications and are emerging contenders for non-volatile data storage applications. In the present work, atomic structure and dynamics of layered defects frequently reported in van der Waals bonded GST based alloys and superlattices are investigated using aberration-corrected STEM. The defects are confined into two atomic layers of GeSb and Te and represent special type of stacking fault. In situ experiments showed that the bilayers can be easily reconfigured into such bilayer stacking faults with subsequent formation of a new van der Waals gap. Depending on the beam dose, the newly formed stacking fault can either reconfigure back to the initial state or move in later direction within the faulty stacking plane. The results of the present work shed insight into mechanism of structural reconfiguration of building blocks in van der Waals bonded GST compounds, also relevant for an understanding of switching mechanisms in iPCMs.