Kiyota, Y.Jeon, I.-R.Jeannin, O.Beau, M.Kawamoto, T.Alemany i Cahner, PereCanadell, Enric, 1950-Mori, T.Fourmigué, M.2022-03-222022-03-222019-09-271463-9076https://hdl.handle.net/2445/184291A 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 S􏰒􏰒􏰒S 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 S􏰒􏰒􏰒S contacts between the TTF stacks lead to more rapidly decreasing M-I transition temperature under various pressures.8 p.application/pdfeng(c) Kiyota, Y. et al., 2019Difracció de raigs XEstructura electrònicaX-rays diffractionElectronic structureinfo:eu-repo/semantics/article7140882022-03-22info:eu-repo/semantics/openAccess