Dresden 2020 – wissenschaftliches Programm
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TT 47.6: Poster
Mittwoch, 18. März 2020, 15:00–19:00, P2/3OG
Dielectric and Fluctuation (Noise) Spectroscopy as Complements Tools to Study Slow Dynamics in Electronic Systems with Frustration — •Giuseppe Cantarella, Merlin Mitschek, Benjamin Kammerbauer, Tatjana Thomas, and Jens Müller — Institute of Physics, Goethe University, Frankfurt (Main), Germany
The fluctuation-dissipation-theorem (FDT) quantifies the relation between the response of a system to external perturbations and its fluctuations at thermal equilibrium. In general the FDT connects the noise power spectral density (PSD) of a system with the dissipative part of susceptibility, χ″. As a consequence, in dielectric system like e.g. glasses, one can measure boths sides of the FDT equation and independently check the validity of the FDT . Our aim is to explore a connection between the dielectric properties of a molecular Mott insulator and the conductance noise PSD, which often shoes a 1/f - type behaviour. As a test system, we chose the spin-liquid  candidate κ-(BEDT-TTF)2Cu2(CN)3, which is a dimer Mott insulator on a frustrated triangular lattice that exhibits anomalous dielectric relaxations which resemble that of relaxor ferroelectric materials with quantum electric dipoles. In this work, we present first results of complementary dielectric susceptibility and current noise measurements.  Phys. Rev. Lett. 107, 095701 (2011)  Phys. Rev. B 82, 125119