Berlin 2024 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 13: Glasses and Glass Transition (joint session CPP/DY)

CPP 13.4: Vortrag

Montag, 18. März 2024, 17:15–17:30, H 0107

Sampling energy landscapes through resistance fluctuations in germanium telluride glass — •Sebastian Walfort, Jakob Ballmaier, Nils Holle, and Martin Salinga — University of Münster, Institute of Materials Physics, Wilhelm-Klemm-Str. 10, 48149 Münster

Germanium telluride (GeTe) is a fragile glass former with a large electrical property contrast between a conductive crystalline phase and highly resistive glass states. It is further possible to repeatedly amorphize and crystallize a nanoscopic, confined volume by applying short voltage pulses, which makes GeTe an interesting model system for observing glassy dynamics. For instance, physical aging following melt-quenching of GeTe glass seems to manifest in a continued evolution of the electronic properties, e.g. in a power-law-like increase of the resistivity. In this experimental study, resistance serves as the observable to probe the structural dynamics of the glass. We demonstrate that, as a consequence of reducing the nanoscopic amorphous volume, individual resistance states can be resolved in time. The fluctuations between these states are measured over a wide temperature range, six orders of magnitude in time and modeled as a (hidden) Markov process. The resulting attempt frequencies and activation energies reveal a complex free energy landscape, where transitions between states are governed by both energetic and entropic contributions to energy barriers. Beyond their relevance for electronic memory applications, these results illustrate the feasibility of the experimental approach to probe the energy landscape of a glass through a fluctuating resistance

Keywords: glass; germanium telluride; noise; fluctuations; energy landscape