Regensburg 2016 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 51: Glasses (joint session CPP/DY, organized by DY)

CPP 51.1: Hauptvortrag

Donnerstag, 10. März 2016, 09:30–10:00, H48

A new look at atomic tunneling systems in glasses containing isotopes with nuclear quadrupol moments — •Andreas Reiser — Kirchhoff Institut für Physik, Universität Heidelberg, INF 227, 69120 Heidelberg, Germany

The physical properties of disordered materials at low temperatures are governed by atomic or molecular tunneling systems. The standard tunneling model explains many properties such as thermal conductivity and heat capacity well. In dynamic experiments for example dielectric susceptibility measurements or polarization echo experiments clear deviations from the standard tunneling model are observed. In particular, the strong influence of nuclear moments inherent in tunneling atoms was proven experimentally recently. We will discuss the mechanism that leads to the interplay of nuclear moments and atomic tunneling systems and will show that at ultra low temperatures a new type of relaxation process enabled by nuclear moments is present. Contrary to previous assumptions this process governs the energy relaxation of the tunneling systems in the limit of lowest temperatures rather than the one phonon process.