Jena 2013 – wissenschaftliches Programm

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GR: Fachverband Gravitation und Relativitätstheorie

GR 23: Poster (permanent)

GR 23.1: Poster

Freitag, 1. März 2013, 14:45–14:45, HS 6

New materials for low noise measurements — •Gerd Hofmann¹, Christian Schwarz¹, Julius Komma¹, Daniel Heinert¹, Paul Seidel¹, Andreas Tünnermann², and Ronny Nawrodt¹ — ¹FSU Jena, Institut für Festkörperphysik, Helmholtzweg 5, D-07743 Jena, Germany — ²FSU Jena, Institut für Angewandte Physik, Albert-Einstein-Strasse 15, D-07745 Jena, Germany

High precision applications like length measurements in gravitational wave oberservatories, laser stabilization, or micro-mechanical systems often suffer from disturbances due to thermal noise. There are two ways to overcome this problem, lowering the temperatures or the mechanical loss in the system. Silicon, sapphire, and gallium arsenide as crystaline materials are of great interest in these communities but not yet fully characterized.

We present a comparision of silicon, sapphire, and gallium arsenide in a wide temperature range from 5 to 300 K. Our measurements on silicon bulk samples show a peak in the mechanical loss around 120 K. A potential loss mechanism is discussed. We further show that Sapphire exhibits a low temperature limit according to the interaction of phonons i.e. Akhiezer damping. In gallium arsenide illumination with light in the visible range increases the mechanical loss. At low temperatures a hysteresis like behaviour can be observed. We link this with the creation of electrons and their interaction with acoustic phonons.

This work is supported by the DFG under contract SFB TR7.