Intermediate regime in Tetrathiafulvalene-Chloranil (TTF-CA) pressure-induced neutral-ionic transition

Abstract

We report a detailed spectroscopic study of the pressure induced neutral-ionic phase transition (NIT) of the mixed-stack charge-transfer (CT) crystal tetrathiafulvalene-chloranil (TTF-CA). We show that the pressure induced phase transition is still first-order and involves the presence of an intermediate disordered phase, defined by the coexistence of two species of different ionicity. Further application of pressure gradually converts this phase into an homogeneous ferroelectric phase with a single ionicity. In addition, we detect strong pretransitional phenomena which anticipate the intermediate phase and are indicative of a precursor dynamic regime dominated by fluctuations.

7 pages, 5 figures

References in corpus (2)

• Dielectric response of modified Hubbard models with neutral-ionic and Peierls transitions
• Giant infrared intensity of the Peierls mode at the neutral-ionic phase transition

Cited by in corpus (6)

• Direct evidence of overdamped Peierls-coupled modes in TTF-CA temperature-induced phase transition
• Separation of Charge Instability and Lattice Symmetry Breaking in an Organic Ferroelectric
• Evolution of ferroelectricity in tetrathiafulvalene-p-chloranil as a function of pressure and temperature
• Phase Competition, Solitons, and Domain Walls in Neutral-Ionic Transition Systems
• Fate of a soliton matter upon symmetry-breaking ferroelectric order
• Experimental Verification of Charge Soliton Excitations in the Ionic Mott-Peierls Ferroelectric, TTF-CA