The ferroelectric Mott-Hubbard phase in organic conductors.

We discuss key issues of the related discovery of the Ferroelectricity (FE) and the Charge Disproportionation (CD) in organic metals, its impact and perspectives. In (TMTTF)(2)X the dielectric susceptibility e demonstrates clear cases of the FE and anti-FE phase transitions. The conductivity gives access to physics of three types of solitons emerging upon cooling. The theory invokes a concept of the Combined Mott-Hubbard State which focuses upon weak processes of electronic Umklapp scattering coming from both a build-in nonequivalence of bonds and a spontaneous one of sites. We propose that the CD and (anti) FE exists hiddenly even in the Se subfamily, (TMTSF)(2)X, giving rise to the unexplained yet low frequency optical peak and the enhanced pseudogap.