TY  - JOUR
A1  - Müller, Jens
A1  - Thomas, Tatjana
T1  - Low-frequency dynamics of strongly correlated electrons in (BEDT-TTF)2X studied by fluctuation spectroscopy
T2  - Crystals
N2  - Fluctuation spectroscopy measurements of quasi-two-dimensional organic charge-transfer salts (BEDT-TTF) 2 X are reviewed. In the past decade, the method has served as a new approach for studying the low-frequency dynamics of strongly correlated charge carriers in these materials. We review some basic aspects of electronic fluctuations in solids, and give an overview of selected problems where the analysis of 1/f -type fluctuations and the corresponding slow dynamics provide a better understanding of the underlying physics. These examples are related to (1) an inhomogeneous current distribution due to phase separation and/or a percolative transition; (2) slow dynamics due to a glassy freezing either of structural degrees of freedom coupling to the electronic properties or (3) of the electrons themselves, e.g., when residing on a highly-frustrated crystal lattice, where slow and heterogeneous dynamics are key experimental properties for the vitrification process of a supercooled charge-liquid. Another example is (4), the near divergence and critical slowing down of charge carrier fluctuations at the finite-temperature critical endpoint of the Mott metal-insulator transition. Here also indications for a glassy freezing and temporal and spatial correlated dynamics are found. Mapping out the region of ergodicity breaking and understanding the influence of disorder on the temporal and spatial correlated fluctuations will be an important realm of future studies, as well as the fluctuation properties deep in the Mott or charge-ordered insulating states providing a connection to relaxor or ordered ferroelectric states studied by dielectric spectroscopy.
KW  - fluctuation spectroscopy
KW  - organic charge-transfer salts
KW  - Mott metal-insulator transition
KW  - glass-like structural ordering
KW  - charge-cluster glass
KW  - percolation
Y1  - 2018
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/47222
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-472229
SN  - 2073-4352
N1  - This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
VL  - 8
IS  - 4, Art. 166
SP  - 1
EP  - 37
PB  - MDPI
CY  - Basel
ER  -