%0 Journal Article
%T Charge localization in one-dimensional tetramerized organic conductors: the special case of (tTTF)2ClO4
%+ Institute of Molecular Physics
%+ Institut des Sciences Chimiques de Rennes (ISCR)
%+ Universität Stuttgart [Stuttgart]
%A Frąckowiak, Arkadiusz
%A Świetlik, Roman
%A Jeannin, Olivier
%A Fourmigué, Marc
%A Li, Weiwu
%A Dressel, Martin
%Z We thank for support from German Academic Exchange Service (DAAD). We are also indebted to Jean-Paul Pouget for discussion.
%< avec comité de lecture
%@ 0953-8984
%J Journal of Physics: Condensed Matter
%I IOP Publishing
%V 31
%N 15
%P 155601
%8 2019-02-18
%D 2019
%R 10.1088/1361-648X/ab00b5
%M 30669131
%K crystal structure
%K IR and Raman spectra
%K charge localization
%K one-dimensional organic conductor
%K phase transition
%Z Chemical Sciences/Material chemistry
%Z Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci]Journal articles
%X We report a detailed structural and spectroscopic study of the 1D 2:1 cation radical salt (tTTF)ClO, where tTTF = trimethylenetetrathiafulvalene, which exhibits a semiconductor-semiconductor phase transition at ca. T = 137 K. Crystal structures are determined above and below the transition; the tTTF molecules in stacks are grouped into weakly interacting tetramers. The reorganization of tTTF stacks is accompanied with an order-disorder transition in anion sublattice. Polarized infrared and Raman spectra of (tTTF)ClO are measured in the broad frequency range as a function of the temperature (10-293 K). The structural and vibrational features are investigated to elucidate the origin of the semiconductor-semiconductor phase transition. We discuss the electron-intramolecular vibration coupling effects in the vibrational spectra of (tTTF)ClO and identify signatures of high- and low-temperature states of charge localization in the tetramerized system. Both the C=C and C-S stretching modes of tTTF give evidence of strong charge distribution fluctuations in conducting stacks for T > 137 K, which are responsible for the appearance of molecules with charge +1e, and charge localization in tTTF tetramers for T < 137 K. The uniqueness of the salt (tTTF)ClO in comparison with other tetramerized 1D systems is discussed.
%G English
%2 https://univ-rennes.hal.science/hal-02015713/document
%2 https://univ-rennes.hal.science/hal-02015713/file/Fr%C4%85ckowiak%20et%20al.%20-%202019%20-%20Charge%20localization%20in%20one-dimensional%20tetramerize.pdf
%L hal-02015713
%U https://univ-rennes.hal.science/hal-02015713
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