The Impact of Discoveries of Ferroelectricity and Charge Disproportionation in Organic Cond.pdfVIP

The Impact of Discoveries of Ferroelectricity and Charge Disproportionation in Organic Conductors. S. Brazovskii 1,2 3 0 1 Laboratoire de Physique Th´eorique et de s Mod`eles Statistiques, CNRS; 0 2 Bˆat.100, Universit´e Paris-Sud, 91405 Orsay cedex, France; r p A e-mail: brazov@ipno.in2p3.fr, http://ipnweb.in2p3.fr∼lptms/membres/brazov/, 3 2 L.D. Landau Institute, Moscow, Russia. ] l (December 2001 ∗) e - r Discoveries of the Ferroelectric anomaly (Nad, Monceau, et al) and of t s t. the related charge disproportionation (Brown et al) call for a revaluation of a the phase diagram of the (T MT T F ) X compounds and return the attention m 2 - d n to the interplay of electronic and structural properties. We shall describe a o c concept of the Combined Mott-Hubbard state as the source for the ferroelec- [ 1 tricity. We shall demonstrate the existence of two types of spinless solitons: v 6 π − solitons, the holons, are observed via the activated conductivity; the non- 7 0 4 integer α− solitons are responsible for the depolarization of the FE order. 0 3 We propose that the (anti) ferroelectricity does exists hiddenly even in Se 0 / t subfamily, giving rise to the unexplained yet optical peak. We remind then a m- the abandoned theory by the author and Yakovenko for the universal phase d n diagram which we contrast with the recent one. o c : v i X r a ∗Followin