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DS: Fachverband Dünne Schichten

DS 39: Focus Session: Resistive Switching by Redox and Phase Change Phenomena VI (Kinetics and Transport in PC materials)

DS 39.3: Vortrag

Donnerstag, 3. April 2014, 10:15–10:30, CHE 89

Phase-Change Materials: Impact of Disorder on Thermal and Electrical Transport — •Karl Simon Siegert¹, Felix Lange¹, and Matthias Wuttig^1,2 — ¹1.Physikalisches Institut (IA), RWTH Aachen University — ²JARA - Fundamentals of Information Technology, RWTH Aachen University, 52056 Aachen, Germany

Disorder plays a vital role in crystalline phase-change compositions along the pseudo-binary line between GeTe and Sb₂Te₃ (GSTs). Many of these compounds crystallize in a rocksalt-like structure where one sublattice is fully occupied by Te atoms, while a random distribution of Ge, Sb and vacancies populates the second sublattice. This gives rise to pronounced configurational disorder which impacts charge transport by localizing electrons [1].
A thorough investigation of GST stoichiometries and measurements of thermal conductivity by the 3ω method towards low temperatures (50 K) demonstrate that thermal transport is affected by disorder as well. Especially disordered vacancies act as efficient point scattering sources and disrupt phonon heat transport. Hence, thermal and electrical conductivities are affected by the same mechanism, albeit on different scales. This finding opens up a pathway to manipulate electrical and thermal transport properties in GSTs through the degree of disorder. Such transport engineering is not only crucial for future data storage devices based on resistance switching, but should be highly valuable for thermoelectrics as well.

T. Siegrist et al., Nat. Mater. 2011, 10, 202-208.