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TT: Fachverband Tiefe Temperaturen
TT 4: Disordered Quantum Systems
TT 4.5: Vortrag
Montag, 16. März 2020, 10:45–11:00, HSZ 204
Slow Dynamics in the Charge-Glass Forming Organic Conductors θ-(BEDT-TTF)2MM′(SCN)4 — •Tatjana Thomas1, Yassine Agarmani1, Tim Thyzel1, Hungwei Sun1, Kenichiro Hashimoto2, Takahiko Sasaki2, Hiroshi Yamamoto3, and Jens Müller1 — 1Institute of Physics, Goethe University Frankfurt, Germany — 2Institute for Materials Research, Tohoku University, Japan — 3Institute for Molecular Science, Okazaki, Japan
The organic charge-transfer salts θ-(ET)2MM′(SCN)4 are considered as model systems to study strongly correlated electron systems under the influence of geometric frustration. Due to strong Coulomb interactions the system exhibits a charge ordering transition, which can be kinetically avoided by fast cooling resulting in a charge-glass state without long-range order [1]. The required cooling rate depends on the degree of charge frustration, where a higher frustration on the triangular lattice within the conducting layers promotes the charge-glass forming ability [2]. Fluctuation spectroscopy has proven to be a powerful tool to study the charge carrier dynamics at low frequencies [3], which have shown to become very slow and heterogeneous when approaching the glass transition, similar to conventional glass-forming liquids [4]. Here, we present systematic noise studies on three compounds MM′=CsCo, RbZn, TlZn with high, medium and low frustration, respectively. From the power spectral density we extract characteristic energies and time scales dominating the resistance noise and compare the results with the quenched states.
[1] Adv. Mater. 29, 1601979;
[2] JPSJ 83, 083602
[3] Crystals 8, 166
[4] Science 357, 1381