Self-organization into ferroelectric and antiferroelectric crystals via the interplay between particle shape and dipolar interaction

Abstract

Ferroelectricity and antiferroelectricity are widely seen in various types of condensed matter and are of technological significance not only due to their electrical switchability but also due to intriguing cross-coupling effects such as electro-mechanical and electro-caloric effects. The control of the two types of dipolar order has practically been made by changing the ionic radius of a constituent atom or externally applying strain for inorganic crystals and by changing the shape of a molecule for organic crystals. However, the basic physical principle behind such controllability involving crystal-lattice organization is still unknown. On the basis of a physical picture that a competition of dipolar order with another type of order is essential to understand this phenomenon, here we develop a simple model system composed of spheroid-like particles with a permanent dipole, which may capture an essence of this important structural transition in organic systems. In this model, we reveal that energetic frustration between the two types of anisotropic interactions, dipolar and steric interactions, is a key to control not only the phase transition but also the coupling between polarization and strain. Our finding provides a fundamental physical principle for self-organization to a crystal with desired dipolar order and realization of large electro-mechanical effects.

Emergent elastic fields induced by topological phase transitions: Impact of molecular chirality and steric anisotropy

“…We also considered the electromagnetic effects in a simple manner by neglecting the electromagnetic interactions between the induced dipoles. The inclusion of dipole–dipole interaction results in controllable polar orders with large mechanical responses ( 56 ). This cross-coupling may also be a key to control emergent elastic fields associated with topological phase transitions induced by anisotropic mechanical stresses ( 32 , 57 ).…”

Emergent elasticity linked to topological phase transitions controlled via molecular chirality and steric anisotropy

“…In this paper, we considered the electromagnetic effects in a simple manner by neglecting the electromagnetic interactions between the induced dipoles. The inclusion of dipole-dipole interaction results in controllable polar orders with large mechanical responses [48]. This cross-coupling may also be a key to control emergent elastic fields associated with topological phase transitions induced by anisotropic mechanical stresses [49,50].…”

On the Evidence of Thermodynamic Self-Organization during Fatigue: A Review

“…A recent impressive work of Pan et al [ 226 ] shows how the concept of patterning at the nanoscale can lead to design better fatigue resistant metals. Similar works related to highly oriented nanotwinned metals for damage tolerant and fatigue-resistance materials can be referred to the work of [ 13 , 227 , 228 , 229 , 230 ].…”