Structure and energetics of a ferroelectric organic crystal of phenazine and chloranilic acid

Abstract

We report first-principles calculations for a ferroelectric organic crystal of phenazine and chloranilic acid molecules. Weak intermolecular interactions are properly treated by using a second version of van der Waals density functional known as vdW-DF2 [K. Lee et al., Phys. Rev. B 82, 081101 (2010)]. Lattice constants, total energies, spontaneous electric polarizations, phonon modes and frequencies, and the energy barrier of proton transfer are calculated and compared with PBE and experiments whenever possible. We show that the donation of one proton from a chloranilic acid molecule to a neighboring phenazine molecule is energetically favorable. This proton transfer is the key structural change that breaks the centrosymmetry and leads to the ferroelectric structure. However, there is no unstable phonon associated with the proton transfer, and an energy barrier of 8 meV is found between the paraelectric and ferroelectric states.

arXiv comment5 pages, 4 figures

References in corpus (5)

• Phonons and related properties of extended systems from density-functional perturbation theory
• A Higher-Accuracy van der Waals Density Functional
• Efficient implementation of a van der Waals density functional: Application to double-wall carbon nanotubes
• Van der Waals density functional: Self-consistent potential and the nature of the van der Waals bond
• Polar distortions in hydrogen bonded organic ferroelectrics

Cited by in corpus (6)

• van der Waals forces in density functional theory: The vdW-DF method
• Next-generation non-local van der Waals density functional
• Screening nature of the van der Waals density functional method: A review and analysis of the many-body physics foundation
• van der Waals density functional with corrected $C_6$ coefficients
• Signatures of van der Waals binding: a coupling-constant scaling analysis
• First-principles study of hydrogen-bonded molecular conductor $\kappa$-H${}_3$(Cat-EDT-TTF/ST)${}_2$