Berlin 2024 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 29: Poster II

MM 29.11: Poster

Tuesday, March 19, 2024, 17:00–19:00, Poster B

The first nanoseconds in the lifetime of a phase change material glass — •Jakob Ballmaier, Sebastian Walfort, and Martin Salinga — University of Münster, Institute of Materials Physics, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany

Small volumes of so called phase change materials (PCMs) can be switched between a conductive crystalline state and high-resistance glass states. This property makes PCMs attractive for novel electronic memory devices, but there remain unresolved challenges. One issue for technical applications is the commonly observed resistance drift, i.e. the power-law-like increase in resistivity from microseconds up to years after the formation of the glass. Many different mechanisms have been proposed to explain this power-law behavior on the usually experimentally accessible time scales, for example by linking it to physical ageing.

On shorter time scales, capacitive currents can prevent accurate resistance measurements. Here we minimise capacitive currents by decoupling the excitation and probing mechanism. The nanoscopic PCM cell is melt-quenched with femtosecond laser pulses while continuously measuring the electrical resistance with a small, constant bias voltage. This measurement scheme allows us to resolve resistance drift from the first nanoseconds over 12 orders in magnitude in time. On short timescales we observe deviations from the well-known power-law behaviour. These observations may help to elucidate the mechanisms underlying resistance drift.

Keywords: phase change materials; glass; structural relaxation; electronic memory; electrical properties