Researchers Develop Model to Explore Transition Behavior of Crystal Lattices


Researchers from the University of Tokyo developed a system revealing the combination of anisotropic steric and dipole effects to induce coupling between polarization and strain

The electrical and mechanical responses of crystal materials and the control of their coupled effect are vital to applications such as ultrasonic generators and non-volatile memory. Although the knowledge of controlling such materials is widely demonstrated in practice, the physical principle behind the controllability through lattice organization is largely undefined. Now, researchers at The University of Tokyo Institute of Industrial Science created a model based on the conflict between different lattice interactions to identify the physical principle. The research was published in Proceedings of the National Academy of Sciences (PNAS) on September 17, 2018.

Crystal structures are composed of atoms or molecules that are arranged in a particular organization and interaction that define the properties of the bulk material. Ferroelectric and antiferroelectric ordering describe long-range dipole-based arrangements of molecules in a lattice. Materials with such order offer electrical switchability and cross-coupling effects. The current model is designed to vary the shape of the molecules in a dipolar lattice to probe the simple physical principle that controls ferroelectric and antiferroelectric order. The simple self-organization model based on spherical particles with a permanent dipole helps to establish the importance of the energetic frustration between the anisotropic steric and dipolar interactions in the self-organization process.

To achieve optimal control of the properties of crystal lattice that are utilized in several applications, it is necessary to understand the underlying principle that governs ferroelectric and antiferroelectric organization and transitions. The researchers carried out thorough modeling of these systems to enhance the rational design of a wide range of materials including non-volatile memory devices. The findings are expected to facilitate important guidelines that lead to highly functional materials. These materials might show cross reaction with electric/magnetic order and deformation or thermal response using substances that show phase transition between ferroelectric ordered phase and antiferroelectric ordered phase, or magnets.



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