We aim to construct novel functional materials by artificially building dynamic ionic spaces within single crystals. For instance, arranging ion-encapsulating macrocyclic molecules in one dimension makes it possible to synthesise single-crystal materials capable of ionic conduction. The materials thus obtained are then characterised in terms of their electrical, magnetic and thermal properties. On the basis of the physical parameters obtained, we go on to explore their application in devices such as solid-state batteries, with a view to constructing novel molecular electronic devices.

Physical and chemical studies of low-dimensional spin-gap compounds are currently being actively pursued. Among these, spin-ladder materials — a class of spin-gap compound lying between one and two dimensions — have attracted considerable interest with regard to their ground state. Moreover, since this class of system possesses a ground state similar to that of the parent compounds of high-temperature superconductors, the theoretical emergence of a superconducting phase through carrier doping has been predicted. Our laboratory therefore seeks to prepare low-dimensional spin-ladder materials based on molecular magnets and to achieve carrier doping within this system, with the aim of constructing a new class of molecular spin-ladder superconductor.

Materials possessing a dipole that can be controlled by the application of an external electric field are known as dielectrics; among these, ferroelectrics, which display spontaneous polarisation, have been extensively studied on account of their considerable potential for application in non-volatile memories, piezoelectric devices and the like. Ferroelectricity has traditionally been regarded as a property arising from the crystal structure, and was therefore assumed to be lost upon miniaturisation, making its expression within a single molecule seem impossible. Our laboratory, by condensing the ion-transfer mechanism of ferroelectrics into a single molecule, was the first in the world to report the existence of molecules that behave as though they were ferroelectrics — so-called single-molecule dielectrics. We are currently working to elucidate the mechanism of single-molecule dielectrics and to develop new single-molecule dielectric materials. We further aim to develop memory devices incorporating single-molecule dielectrics.