Berlin 2015 – scientific programme
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DS: Fachverband Dünne Schichten
DS 36: Poster Session I
DS 36.5: Poster
Thursday, March 19, 2015, 09:30–12:00, Poster A
Photoelectron Spectroscopy Study of Disorder Controlled Ge1Sb2Te4 — •Matthias M. Dück1, Felix R. L. Lange1, Tobias Schäfer1, Sebastian Mäder1, Hanno Volker1, and Matthias Wuttig1,2 — 1I. Physikalisches Institut (IA), RWTH Aachen University, D-52056 Aachen, Germany — 2JARA - Fundamentals of Information Technology, RWTH Aachen University, 52056 Aachen, Germany
Phase Change Materials (PCM) display a significant contrast in optical reflectivity and electrical resistivity upon crystallization, which is attributed to the formation of resonant bonding in the crystalline state. Due to the long-term stability of the phases as well as the ability to switch between the states reversibly on a nanosecond time scale, PCM are well suitable for fast non-volatile solid state memory devices.
In 2011, Siegrist et al. identified structural disorder to cause an Anderson-like insulator-to-metal transition in most phase-change materials along the line between GeTe and Sb2Te3 [1]. In these materials Te atoms form an anion sublattice while the second site is randomly occupied by Ge, Sb and a stoichiometric amount of vacancies. Via annealing these cation sites can be ordered, which finally triggers the transition from insulating to metallic behavior. Here we investigate this transition by means of photoelectron spectroscopy supported by Hall- and four-point resistivity as well as X-ray diffractometry measurements.
[1] Siegrist et.al. Disorder-induced localization in crystalline phase-change materials. Nature Mater. 10, 202-208 (2011)