Dresden 2014 – scientific programme

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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 39.5: Talk

Thursday, April 3, 2014, 10:45–11:00, CHE 89

Structure and Transport Properties of Pseudo Ternary SnTe, GeTe, Sb₂Te₃ Chalcogenides — •Felix R. L. Lange¹, Stefan Jakobs¹, Tim Labohm¹, Jan Kirchhof¹, Tobias Schäfer¹, K. Simon Siegert¹, and Matthias Wuttig^1,2 — ¹I. Physikalisches Institut (IA), RWTH Aachen University, 52056 Aachen, Germany — ²JARA - Fundamentals of Information Technology, RWTH Aachen University, 52056 Aachen, Germany

Ternary chalcogenides along the line between GeTe and Sb₂Te₃ have caught interest due to their high degree of disorder in the crystalline phase. Only recently Siegrist et al. reported an insulator-to-metal transition in the crystalline phase [1]. Depending on the annealing temperature of the thin films the electrical resistivity is either thermally activated or develops metallic at elevated temperatures. While little change is noticed on the carrier concentration the electrical resistance spans over six orders of magnitude at room temperature. Based on DFT calculations Zhang et al. identified clusters of vacancies to localize the wave functions responsible for charge transport in the early meta-stable cubic phase [2]. Dissolution of these clusters upon annealing then leads to a delocalization of the corresponding wave functions concomitant with the transition to the metallic state. Here we explore pseudo ternary alloys of SnTe, GeTe and Sb₂Te₃ in order to utilize both, stoichiometry and annealing condition to adjust the degree of disorder concomitant with tailored transport properties.
T. Siegrist et al., Nat. Mater. 10, 202-208 (2011)
W. Zhang et al., Nat. Mater. 11, 952-956 (2012)