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Title: | Electronic engineering of a tetrathiafulvalene charge-transfer salt via reduced symmetry induced by combined substituents |
Author: | Kiyota, Y. Jeon, I.-R. Jeannin, O. Beau, M. Kawamoto, T. Alemany i Cahner, Pere Canadell, Enric, 1950- Mori, T. Fourmigué, M. |
Keywords: | Difracció de raigs X Estructura electrònica X-rays diffraction Electronic structure |
Issue Date: | 27-Sep-2019 |
Publisher: | Royal Society of Chemistry |
Abstract: | A 1 : 1 metallic charge-transfer salt is obtained by cosublimation of (Z,E)-(SMe)2Me2TTF and TCNQ. X-ray diffraction studies confirm the formation of segregated stacks comprising donor and acceptor molecules in [(E)-(SMe)2Me2TTF](TCNQ). The crystal packing features lateral SS interactions between TTF stacks, which is in sharp contrast to that in (TTF)(TCNQ). Structural analysis and theoretical studies afford a partial charge-transfer (r E 0.52), leading to a system with the electronic structure close to quarter-filled. Resistivity measurements reveal that this material behaves as a metal down to 56 K and 22 K at 1 bar and 14.9 kbar, respectively. The thermopower is negative in the metallic regime, indicating the dominant role of the acceptor stacks for the observed conducting behavior. Analysis of single- crystal EPR spectra shows the remaining spin susceptibility at 4.3 K, suggesting the importance of the Hubbard U correction. These results highlight the judicious engineering of electronic and geometrical effects on the TTF core; the combined use of methyl and thiomethyl groups has decreased the TCNQ bandwidth while maintaining the segregated stacks, converting the metal to insulator (M-I) transition to more 4kF like. In addition, the enhanced SS contacts between the TTF stacks lead to more rapidly decreasing M-I transition temperature under various pressures. |
Note: | Versió postprint del document publicat a: https://doi.org/10.1039/C9CP04320A |
It is part of: | Physical Chemistry Chemical Physics, 2019, vol. 40, p. 22639-22646 |
URI: | http://hdl.handle.net/2445/184291 |
Related resource: | https://doi.org/10.1039/C9CP04320A |
ISSN: | 1463-9076 |
Appears in Collections: | Articles publicats en revistes (Ciència dels Materials i Química Física) Articles publicats en revistes (Institut de Química Teòrica i Computacional (IQTCUB)) |
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