Evolution of ferroelectricity in tetrathiafulvalene-p-chloranil as a function of pressure and temperature

Abstract

The neutral-to-ionic phase transition in the mixed-stack charge-transfer complex tetrathiafulvalene-p-chloranil (TTF-CA) has been studied by pressure-dependent infrared spectroscopy up to p=11 kbar and down to low temperatures, T = 10 K. By tracking the C=O antisymmetric stretching mode of CA molecules, we accurately determine the ionicity of TTF-CA in the pressure-temperature phase diagram. At any point the TTF-CA crystal bears only a single ionicity; there is no coexistence region or an exotic high-pressure phase. Our findings shed new light on the role of electron-phonon interaction in the neutral-ionic transition.

6 pages, 4 figures, accepted for publication in JCP

References in corpus (2)

• Absence of charge order in the dimerized κ-phase BEDT-TTF salts
• Charge Order Breaks Magnetic Symmetry in Molecular Quantum Spin Chains

Cited by in corpus (5)

• Separation of Charge Instability and Lattice Symmetry Breaking in an Organic Ferroelectric
• Phase Competition, Solitons, and Domain Walls in Neutral-Ionic Transition Systems
• Fate of a soliton matter upon symmetry-breaking ferroelectric order
• Molecular Dynamics at Electrical- and Optical-Driven Phase Transitions Time-Resolved Infrared Studies Using Fourier-Transform Spectrometers
• Experimental Verification of Charge Soliton Excitations in the Ionic Mott-Peierls Ferroelectric, TTF-CA