Berlin 2018 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 30: Poster Session: Disordered Quantum Systems

TT 30.7: Poster

Montag, 12. März 2018, 15:00–19:00, Poster B

Dielectric Properties of a Brominated Molecular Glass at Low Frequencies and Low Temperatures — •Nicole Aßmann, Annina Luck, Benedikt Frey, Andreas Fleischmann, Andreas Reiser, and Christian Enss — Kirchhoff-Institute for Physics, Heidelberg University, D-69120 Heidelberg

The low temperature behavior of amorphous solids is determined by atomic tunneling systems and can be described by the phenomenological standard tunneling model (STM). In the last two decades, several deviations from STM-like behavior have been observed which triggered a number of refinements of this model taking microscopic details of the tunneling entity and motion as well as the presence of nuclear moments into account. In order to study particularly the effect of large nuclear quadrupole splittings on the structure and dynamics of atomic tunneling systems we investigated brominated Bisphenol A diglycidether (BrDGEBA). This simply structured molecule contains about 5 % bromine which carries a very large quadrupole moment. In addition to its vitreous behaviour and well known quadrupole splitting of 250 MHz, it provides the possibility of adjusting the bromine concentration of the sample by mixing it with its unbrominated version. As a first attempt we measured the dielectric properties of an undiluted sample between 60 Hz and 16 kHz at temperatures down to 10 mK and ascertained large deviations from the STM at low frequencies combined with low temperatures.